[PATCH] Do not call fetch() when we have it.

[PATCH] Do not call fetch() when we have it.

Currently pull() calls fetch() without checking whether we have
the wanted object but all of the existing fetch()
implementations perform this check and return success
themselves.  This patch moves the check to the caller.

I will be sending a trivial git-local-pull which depends on
this in the next message.

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