The current test code for octavia requires DVR extensions to be
present on the Neutron API server.
We need to conditionally enable this based on enabled extensions to
allow the test to operate on multiple deployment configurations.
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.
Frode Nordahl
Chris MacNaughton