pack-objects: Prefer shallower deltas if the size is equal
pack-objects: Prefer shallower deltas if the size is equal

Change "try_delta" so that if it finds a delta that has the same size
but shallower depth than the existing delta, it will prefer the
shallower one.  This makes certain delta trees vastly less deep.

Signed-off-by: Brian Downing <47d0c8984e39bbcb35e626c3cdbd84e5cd88ece4@lavos.net>
Signed-off-by: Junio C Hamano <a6723cc3f76163bf7adb636a73ac3b0ceb3e6b9b@pobox.com>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git