The existing code lead to intermittent failures as there are a few
Neutron ports tagged with ``device:owner`` ``compute:nova`` that
has nothing to do with our payload instances.
Get IP information by asking Nova to list instances instead.
Setup can be used standalone by other charms consuming the
``octavia-diskimage-retrofit`` charm for their testing purposes.
Tests the charms actions.
Full end to end test will be done by consuming this charm in the
``octavia`` charm tests.