Add Constraints support
Add Constraints support

To be co-installable with other OpenStack projects and have consistent
testing it's a good idea (tm) to use constraints when creating tox
environments.

Change-Id: Ib79448302b66ded52763037cc58261058ccda27a

openstack/ironic-ui,openstack/ironic-ui,openstack/ironic-ui,openstack/ironic-ui