fixup! maintenance: add new vfs-cache-move maintenance task

Author: mjcheetham

builtin/gc.c

@@ -1442,6 +1442,11 @@ static void migrate_pack(const char *srcdir, const char *dstdir,
 
 		strbuf_setlen(&src, srclen);
 		strbuf_addstr(&src, files[i].ext);
+
+		/* Files that never existed in originally have no clean up.*/
+		if (!file_exists(src.buf))
+			continue;
+
 		if (unlink(src.buf))
 			warning_errno(_("failed to delete '%s'"), src.buf);
 	}