Add query for nova fixed ip unit test bug 1333410

There are actually at least 6 unit test cases failing related to
fixed/floating IPs but we can fingerprint one to catch them all most
likely, as running logstash queries against a sample of 3 of them yield
the same results, i.e. shows up around 6/23, check and gate failures,
same number of hits and same change sets.

Related-Bug: #1333410

Change-Id: If4ca34c0bbd52222c9c0aedce09bb0c32bc3074e