Fix double DELETE request for floating ips

There is douple delete request for floating ips
deletetion for the same floating ip.
So if ip delete in tests, we do not try to delete
it in TearDown any more

Change-Id: Ifc08be901ddf09e4895c79f5cdc134384331ced9
Closes-Bug: #1262795
Merge "Fix double DELETE request for floating ips"