Filter floating/fixed ip tests for tempest-cells

Fixed ips do not work with current nova-cells.  Floating ips partially
work depending on which database the floating ip pool(s) are created in,
but they don't just work out of the box.  So these tests should be
disabled so we can get closer to a passing job.

Change-Id: I77c011ed3a36757519e07030ced779cee8b108b9
Merge "Filter floating/fixed ip tests for tempest-cells"