refs: do not execute reference-transaction hook on packing refs
The reference-transaction hook is supposed to track logical changes to
references, but it currently also gets executed when packing refs in a
repository. This is unexpected and ultimately not all that useful:
packing refs is not supposed to result in any user-visible change to the
refs' state, and it ultimately is an implementation detail of how refs
stores work.
Fix this excessive execution of the hook when packing refs.
Reported-by: Waleed Khan <me@waleedkhan.name>
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>