This new option is meant to be used in conjunction with the
options "git repack -a -d" usually invokes the underlying
pack-objects with.  When this option is given, objects unreachable
from the refs in packs named with --unpacked= option are added
to the resulting pack, in addition to the reachable objects that
are not in packs marked with *.keep files.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>