This allows to maintain the default behavior unchanged while making it
possible to force clean.
Follow-up to https://review.openstack.org/#/c/145921/
Change-Id: Ie5733b22bda9cdd7d08f5c5ecc5a3d94b984a125
When running Docker, you can unknowingly use up a lot
of memory. This tool will make it easier to clean up
Docker.
Change-Id: Icfd780f12b01956093a2933dd484cde1e2d6d5bc