midx: verify: add midx packfiles to the packed_git list

Fix "git multi-pack-index verify" to handle repos with thousands
of packfiles.

Midx verify adds the individual "packed_git" structures to the
multi_pack_index.packs array, but it does not add them to the
"repository.objects.packed_git" list.  During the verification
code, each packfile is opened and scanned.  And "pack_open_fds"
is incremented.  If "pack_open_fds" equals the "pack_max_fds"
open_packed_git_1() calls close_one_pack() to LRU-style close
an already open packfile.  But because the packfiles were never
added to the "packed_git" list, close_one_pack() does nothing.
If there are very many packfiles, Git runs out of file descriptors
and fails.

Note that this was observed on Windows when build with GCC and
in a repository with more than (2048-25) packfiles.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>

Author: jeffhostetler

midx.c

@@ -1014,6 +1014,9 @@ int verify_midx_file(const char *object_dir)
 	for (i = 0; i < m->num_packs; i++) {
 		if (prepare_midx_pack(m, i))
 			midx_report("failed to load pack in position %d", i);
+
+		if (m->packs[i])
+			install_packed_git(the_repository, m->packs[i]);
 	}
 
 	for (i = 0; i < 255; i++) {