[PATCH] Also parse objects we already have

In the case where we don't know from context what type an object is, but
we don't have to fetch it, we need to parse it to determine the type
before processing it.

Signed-off-by: Daniel Barkalow <barkalow@iabervon.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>