By splitting up Zaza from the openstack-charms specific tests,
we can more easily guarantee test stability, while not harming
out ability to improve on the testing library during a cycle.
This change backports the zaza namespace change landing, and
adds a stable branch of the zaza-openstack-charms project to
the test-dependencies.
Change-Id: I63082395ab1a47fd19c8b50f5eae4e2f4c73393b
b163bd2d02