cmd_clone(): free or UNLEAK further pointers when finished

UNLEAK(repo) because repo can point either to argv[0], or a malloc'd string
returned by absolute_pathdup().

We also add one free in the middle of cmd_clone(): path will be overwritten later,
hence we should free it after the first use to avoid a leak.

This squashes numerous direct and indirect leaks encountered while running t0001
with LSAN. A selection of LSAN outputs are included below (the full list is
omitted because it's just too long and uninteresting).

Direct leak of 178 byte(s) in 1 object(s) allocated from:
    #0 0x49a53d in malloc /home/abuild/rpmbuild/BUILD/llvm-11.0.0.src/build/../projects/compiler-rt/lib/asan/asan_malloc_linux.cpp:145:3
    #1 0x9a6ff4 in do_xmalloc /home/ahunt/oss-fuzz/git/wrapper.c:41:8
    #2 0x9a6fca in xmalloc /home/ahunt/oss-fuzz/git/wrapper.c:62:9
    #3 0x8ce296 in copy_ref /home/ahunt/oss-fuzz/git/remote.c:885:8
    #4 0x8d2ebd in guess_remote_head /home/ahunt/oss-fuzz/git/remote.c:2215:10
    #5 0x51d0c5 in cmd_clone /home/ahunt/oss-fuzz/git/builtin/clone.c:1308:4
    #6 0x4cd60d in run_builtin /home/ahunt/oss-fuzz/git/git.c:453:11
    #7 0x4cb2da in handle_builtin /home/ahunt/oss-fuzz/git/git.c:704:3
    git#8 0x4ccc37 in run_argv /home/ahunt/oss-fuzz/git/git.c:771:4
    git#9 0x4cac29 in cmd_main /home/ahunt/oss-fuzz/git/git.c:902:19
    git#10 0x69c45e in main /home/ahunt/oss-fuzz/git/common-main.c:52:11
    git#11 0x7f6a459d5349 in __libc_start_main (/lib64/libc.so.6+0x24349)

Direct leak of 165 byte(s) in 1 object(s) allocated from:
    #0 0x49a53d in malloc /home/abuild/rpmbuild/BUILD/llvm-11.0.0.src/build/../projects/compiler-rt/lib/asan/asan_malloc_linux.cpp:145:3
    #1 0x9a6fc4 in do_xmalloc /home/ahunt/oss-fuzz/git/wrapper.c:41:8
    #2 0x9a6f9a in xmalloc /home/ahunt/oss-fuzz/git/wrapper.c:62:9
    #3 0x8ce266 in copy_ref /home/ahunt/oss-fuzz/git/remote.c:885:8
    #4 0x51e9bd in wanted_peer_refs /home/ahunt/oss-fuzz/git/builtin/clone.c:574:21
    #5 0x51cfe1 in cmd_clone /home/ahunt/oss-fuzz/git/builtin/clone.c:1284:17
    #6 0x4cd60d in run_builtin /home/ahunt/oss-fuzz/git/git.c:453:11
    #7 0x4cb2da in handle_builtin /home/ahunt/oss-fuzz/git/git.c:704:3
    git#8 0x4ccc37 in run_argv /home/ahunt/oss-fuzz/git/git.c:771:4
    git#9 0x4cac29 in cmd_main /home/ahunt/oss-fuzz/git/git.c:902:19
    git#10 0x69c42e in main /home/ahunt/oss-fuzz/git/common-main.c:52:11
    git#11 0x7f8fef0c2349 in __libc_start_main (/lib64/libc.so.6+0x24349)

Direct leak of 165 byte(s) in 1 object(s) allocated from:
    #0 0x49a6b2 in calloc /home/abuild/rpmbuild/BUILD/llvm-11.0.0.src/build/../projects/compiler-rt/lib/asan/asan_malloc_linux.cpp:154:3
    #1 0x9a72f2 in xcalloc /home/ahunt/oss-fuzz/git/wrapper.c:140:8
    #2 0x8ce203 in alloc_ref_with_prefix /home/ahunt/oss-fuzz/git/remote.c:867:20
    #3 0x8ce1a2 in alloc_ref /home/ahunt/oss-fuzz/git/remote.c:875:9
    #4 0x72f63e in process_ref_v2 /home/ahunt/oss-fuzz/git/connect.c:426:8
    #5 0x72f21a in get_remote_refs /home/ahunt/oss-fuzz/git/connect.c:525:8
    #6 0x979ab7 in handshake /home/ahunt/oss-fuzz/git/transport.c:305:4
    #7 0x97872d in get_refs_via_connect /home/ahunt/oss-fuzz/git/transport.c:339:9
    git#8 0x9774b5 in transport_get_remote_refs /home/ahunt/oss-fuzz/git/transport.c:1388:4
    git#9 0x51cf80 in cmd_clone /home/ahunt/oss-fuzz/git/builtin/clone.c:1271:9
    git#10 0x4cd60d in run_builtin /home/ahunt/oss-fuzz/git/git.c:453:11
    git#11 0x4cb2da in handle_builtin /home/ahunt/oss-fuzz/git/git.c:704:3
    git#12 0x4ccc37 in run_argv /home/ahunt/oss-fuzz/git/git.c:771:4
    git#13 0x4cac29 in cmd_main /home/ahunt/oss-fuzz/git/git.c:902:19
    git#14 0x69c45e in main /home/ahunt/oss-fuzz/git/common-main.c:52:11
    git#15 0x7f6a459d5349 in __libc_start_main (/lib64/libc.so.6+0x24349)

Direct leak of 178 byte(s) in 1 object(s) allocated from:
    #0 0x49a53d in malloc /home/abuild/rpmbuild/BUILD/llvm-11.0.0.src/build/../projects/compiler-rt/lib/asan/asan_malloc_linux.cpp:145:3
    #1 0x9a6ff4 in do_xmalloc /home/ahunt/oss-fuzz/git/wrapper.c:41:8
    #2 0x9a6fca in xmalloc /home/ahunt/oss-fuzz/git/wrapper.c:62:9
    #3 0x8ce296 in copy_ref /home/ahunt/oss-fuzz/git/remote.c:885:8
    #4 0x8d2ebd in guess_remote_head /home/ahunt/oss-fuzz/git/remote.c:2215:10
    #5 0x51d0c5 in cmd_clone /home/ahunt/oss-fuzz/git/builtin/clone.c:1308:4
    #6 0x4cd60d in run_builtin /home/ahunt/oss-fuzz/git/git.c:453:11
    #7 0x4cb2da in handle_builtin /home/ahunt/oss-fuzz/git/git.c:704:3
    git#8 0x4ccc37 in run_argv /home/ahunt/oss-fuzz/git/git.c:771:4
    git#9 0x4cac29 in cmd_main /home/ahunt/oss-fuzz/git/git.c:902:19
    git#10 0x69c45e in main /home/ahunt/oss-fuzz/git/common-main.c:52:11
    git#11 0x7f6a459d5349 in __libc_start_main (/lib64/libc.so.6+0x24349)

Direct leak of 165 byte(s) in 1 object(s) allocated from:
    #0 0x49a6b2 in calloc /home/abuild/rpmbuild/BUILD/llvm-11.0.0.src/build/../projects/compiler-rt/lib/asan/asan_malloc_linux.cpp:154:3
    #1 0x9a72f2 in xcalloc /home/ahunt/oss-fuzz/git/wrapper.c:140:8
    #2 0x8ce203 in alloc_ref_with_prefix /home/ahunt/oss-fuzz/git/remote.c:867:20
    #3 0x8ce1a2 in alloc_ref /home/ahunt/oss-fuzz/git/remote.c:875:9
    #4 0x72f63e in process_ref_v2 /home/ahunt/oss-fuzz/git/connect.c:426:8
    #5 0x72f21a in get_remote_refs /home/ahunt/oss-fuzz/git/connect.c:525:8
    #6 0x979ab7 in handshake /home/ahunt/oss-fuzz/git/transport.c:305:4
    #7 0x97872d in get_refs_via_connect /home/ahunt/oss-fuzz/git/transport.c:339:9
    git#8 0x9774b5 in transport_get_remote_refs /home/ahunt/oss-fuzz/git/transport.c:1388:4
    git#9 0x51cf80 in cmd_clone /home/ahunt/oss-fuzz/git/builtin/clone.c:1271:9
    git#10 0x4cd60d in run_builtin /home/ahunt/oss-fuzz/git/git.c:453:11
    git#11 0x4cb2da in handle_builtin /home/ahunt/oss-fuzz/git/git.c:704:3
    git#12 0x4ccc37 in run_argv /home/ahunt/oss-fuzz/git/git.c:771:4
    git#13 0x4cac29 in cmd_main /home/ahunt/oss-fuzz/git/git.c:902:19
    git#14 0x69c45e in main /home/ahunt/oss-fuzz/git/common-main.c:52:11
    git#15 0x7f6a459d5349 in __libc_start_main (/lib64/libc.so.6+0x24349)

Direct leak of 105 byte(s) in 1 object(s) allocated from:
    #0 0x49a859 in realloc /home/abuild/rpmbuild/BUILD/llvm-11.0.0.src/build/../projects/compiler-rt/lib/asan/asan_malloc_linux.cpp:164:3
    #1 0x9a71f6 in xrealloc /home/ahunt/oss-fuzz/git/wrapper.c:126:8
    #2 0x93622d in strbuf_grow /home/ahunt/oss-fuzz/git/strbuf.c:98:2
    #3 0x937a73 in strbuf_addch /home/ahunt/oss-fuzz/git/./strbuf.h:231:3
    #4 0x939fcd in strbuf_add_absolute_path /home/ahunt/oss-fuzz/git/strbuf.c:911:4
    #5 0x69d3ce in absolute_pathdup /home/ahunt/oss-fuzz/git/abspath.c:261:2
    #6 0x51c688 in cmd_clone /home/ahunt/oss-fuzz/git/builtin/clone.c:1021:10
    #7 0x4cd60d in run_builtin /home/ahunt/oss-fuzz/git/git.c:453:11
    git#8 0x4cb2da in handle_builtin /home/ahunt/oss-fuzz/git/git.c:704:3
    git#9 0x4ccc37 in run_argv /home/ahunt/oss-fuzz/git/git.c:771:4
    git#10 0x4cac29 in cmd_main /home/ahunt/oss-fuzz/git/git.c:902:19
    git#11 0x69c45e in main /home/ahunt/oss-fuzz/git/common-main.c:52:11
    git#12 0x7f6a459d5349 in __libc_start_main (/lib64/libc.so.6+0x24349)

Author: ahunt

builtin/clone.c

@@ -967,7 +967,7 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 	char *path, *dir, *display_repo = NULL;
 	int dest_exists, real_dest_exists = 0;
 	const struct ref *refs, *remote_head;
-	const struct ref *remote_head_points_at;
+	const struct ref *remote_head_points_at = NULL;
 	const struct ref *our_head_points_at;
 	struct ref *mapped_refs;
 	const struct ref *ref;
@@ -1017,9 +1017,10 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 	repo_name = argv[0];
 
 	path = get_repo_path(repo_name, &is_bundle);
-	if (path)
+	if (path) {
+		free(path);
 		repo = absolute_pathdup(repo_name);
-	else if (strchr(repo_name, ':')) {
+	} else if (strchr(repo_name, ':')) {
 		repo = repo_name;
 		display_repo = transport_anonymize_url(repo);
 	} else
@@ -1393,6 +1394,12 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 	strbuf_release(&reflog_msg);
 	strbuf_release(&branch_top);
 	strbuf_release(&key);
+	free_refs(mapped_refs);
+	free_refs((void *)remote_head_points_at);
+	free_refs((void *)refs);
+	free(dir);
+	free(path);
+	UNLEAK(repo);
 	junk_mode = JUNK_LEAVE_ALL;
 
 	strvec_clear(&transport_ls_refs_options.ref_prefixes);