Add Python3 xena unit tests
Add Python3 xena unit tests

This is an automatically generated patch to ensure unit testing
is in place for all the of the tested runtimes for xena.

See also the PTI in governance [1].

[1]: https://governance.openstack.org/tc/reference/project-testing-interface.html

Change-Id: Ib901dde11f0f8bd6d6e2ae320c5c45b9d4548de0

openstack/designate-dashboard,openstack/designate-dashboard,openstack/designate-dashboard