Integration with oslo.messaging library

Port Trove to use oslo messaging library instead of obsolete messaging
code from oslo incubator.

Change-Id: Ibd886f3cb4a45250c7c434b3af711abee266671c
Implements: blueprint rpc-versioning

trove/tests/unittests/cluster/test_cluster.py

@@ -38,6 +38,7 @@ CONF = cfg.CONF
 class ClusterTest(TestCase):
     def setUp(self):
         super(ClusterTest, self).setUp()
+        task_api.API.get_client = Mock()
         self.cluster_id = str(uuid.uuid4())
         self.cluster_name = "Cluster" + self.cluster_id
         self.tenant_id = "23423432"