Previous changes (Ifa270536481fcb19c476c9c62d89e6c5cae36ca1 and
I44251db399cd73390a9d1931a7f253662002ba10) separated out test setup
that had to import Neutron to allow the api tests to run. The api
tests previously imported Tempest, and errors would result if both
Neutron and Tempest were imported in the same test run. Now that the
api tests do not import Tempest, the base test cases can be simplified
by reversing the referenced changes.
A dependent change to neutron-fwaas removes reference to testlib
plugin: I0f2098cfd380fb6978d643cfd09bcc5cf8ddbdb9