git-bundle: various fixups
verify_bundle() returned with an error early only when all
prerequisite commits were missing. It should error out much
earlier when some are missing.
When the rev-list is limited in ways other than revision range
(e.g. --max-count or --max-age), create_bundle() listed all
positive refs given from the command line as if they are
available, but resulting pack may not have some of them. Add a
logic to make sure all of them are included, and error out
otherwise.
Signed-off-by: Junio C Hamano <junkio@cox.net>