[PATCH] Teach read-tree about commit objects

[PATCH] Teach read-tree about commit objects

Updates read-tree to use read_tree_with_tree_or_commit_sha1()
function.  The command can take either tree or commit IDs with
this patch.

The change involves a slight modification of how it recurses down
the tree.  Earlier the caller only supplied SHA1 and the recurser
read the object using it, but now it is the caller's responsibility
to read the object and give it to the recurser.  This matches the
way recursive behaviour is done in other tree- related commands.

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