Use constraints everywhere
Use constraints everywhere

Infra now supports constraints everywhere, remove now unused
workarounds.

For more information about constraints see:
http://lists.openstack.org/pipermail/openstack-dev/2016-August/101474.html

Change-Id: If8a11e1c4201570e1c1fa90ce35852704ff3bf13

stackforge/monasca-persister,openstack/monasca-persister,openstack/monasca-persister,stackforge/monasca-persister,stackforge/monasca-persister,sapcc/monasca-persister,openstack/monasca-persister