Updated openstack/openstack
Project: openstack-dev/devstack  59d9cecb163c2a0ffa636b85149bb3c7e2c4626c
null
bring back oslo_clean

oslo_clean is still needed at this point, removing it was
premature, especially for upgrade testing.

Change-Id: Ic845d835f587923423f83ac698bd825f3fa5dd1f