get rid of unlinkold

We currently have two methods for cleaning up object directories - unlinkold in
the object server and hash_suffix in the replicator.

This modifies the object server to reuse the more complete hash_suffix logic.

Change-Id: Id2fd83caad979bfd446d52a775a1fa373a670cf1
Signed-off-by: Peter Portante <peter.portante@redhat.com>
Merge "get rid of unlinkold"