Description of problem:
all OSP14 unit and functional tests fail

Version-Release number of selected component (if applicable):
latest OSP14, 20180906.1 puddle

How reproducible:
100%

Backtrace:
Failed to import test module: neutron.tests.unit.tests.test_base
Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/unittest2/loader.py", line 445, in _find_test_path
    module = self._get_module_from_name(name)
  File "/usr/lib/python2.7/site-packages/unittest2/loader.py", line 384, in _get_module_from_name
    __import__(name)
  File "neutron/tests/unit/tests/test_base.py", line 23, in <module>
    from neutron.tests import base
  File "neutron/tests/base.py", line 30, in <module>
    from neutron_lib import fixture
  File "/usr/lib/python2.7/site-packages/neutron_lib/fixture.py", line 29, in <module>
    from neutron_lib.tests.unit import fake_notifier
ImportError: No module named tests.unit

The RPCFixture was rehomed in neutron-lib in the Rocky cycle, but depends on fake_notifier from tests (which are excluded in current python-neutron-lib)