Set policy_opt defaults in placement deploy unit test

Without this change, tests can intermittently fail with NoSuchOptError
when a single process does not have the ConfigFixture running before
this test. This change ensure the opts are registered and defaulted.

Change-Id: I6a4873726e3e7fe0d4db3d1dea61309702b8f24b
Closes-Bug: #1788176

nova/tests/unit/api/openstack/placement/test_deploy.py

@@ -14,6 +14,7 @@
 """Unit tests for the deply function used to build the Placement service."""
 
 from oslo_config import cfg
+from oslo_policy import opts as policy_opts
 import testtools
 import webob
 
@@ -34,6 +35,8 @@ class DeployTest(testtools.TestCase):
                           group='keystone_authtoken')
         # ensure that the auth_token middleware is chosen
         CONF.set_override('auth_strategy', 'keystone', group='api')
+        # register and default policy opts (referenced by deploy)
+        policy_opts.set_defaults(CONF)
         app = deploy.deploy(CONF)
         req = webob.Request.blank('/resource_providers', method="GET")