git-pack-refs --prune

git-pack-refs --prune

"git pack-refs --prune", after successfully packing the existing
refs, removes the loose ref files.  It tries to protect against
race by doing the usual lock_ref_sha1() which makes sure the
contents of the ref has not changed since we last looked at.

Also we do not bother trying to prune what was already packed, and
we do not try pruning symbolic refs.

Signed-off-by: Junio C Hamano <junkio@cox.net>