[dev] Extracted placement repo is now used in devstack/grenade jobs on master

Now that [1] is merged, the extracted openstack/placement repo is being used in devstack and grenade testing for changes on master. This is part of a series of changes for the extraction [2] from nova but it's likely the one that will have the most impact (if any) to other projects on a daily basis because of our CI system. So this is just an FYI in case something goes off the rails in the near future, hit us in the mailing list or #openstack-placement (or #openstack-nova) IRC channels. [1] https://review.openstack.org/#/c/600162/ [2] https://etherpad.openstack.org/p/BER-placement-extract -- Thanks, Matt