Kill finally, use addCleanUp

Remove the finally usage for cleanup in the floating_ips tests and
in the test_services tests.

The finally blocks may try to delete resources which are even does not
exists, and or referencing to an undefined variables, which could hide
the original exceptions from the resource creation operations.

Change-Id: I23740553c793dcb2904a561b8f2ce801137e32d8
Merge "Kill finally, use addCleanUp"