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: I1c6660635b26a9e0106d34eab8d63990b6cd2768

ChameleonCloud/blazar,openstack/blazar,openstack/blazar,ChameleonCloud/blazar