[PATCH] Adjust fsck-cache to packed GIT and alternate object pool.

[PATCH] Adjust fsck-cache to packed GIT and alternate object pool.

The fsck-cache complains if objects referred to by files in .git/refs/
or objects stored in files under .git/objects/??/ are not found as
stand-alone SHA1 files (i.e.  found in alternate object pools
GIT_ALTERNATE_OBJECT_DIRECTORIES or packed archives stored under
.git/objects/pack).

Although this is a good semantics to maintain consistency of a single
.git/objects directory as a self contained set of objects, it sometimes
is useful to consider it is OK as long as these "outside" objects are
available.

This commit introduces a new flag, --standalone, to git-fsck-cache.
When it is not specified, connectivity checks and .git/refs pointer
checks are taught that it is OK when expected objects do not exist under
.git/objects/?? hierarchy but are available from an packed archive or in
an alternate object pool.

Signed-off-by: Junio C Hamano <junkio@cox.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>