VOL-572: Integration testing with Kubernetes

Updated test_dispatcher to run in the single-node Kubernetes environment, as well as
in docker-compose.

Test_dispatcher.py requires the 'scenario' object literal defined in test_voltha_xpon.py,
which it imports from that file. The import operation appears to cause code in test_voltha_xpon.py
to execute, code which requires containers to be already running. This defeats the automation
that was already built into test_dispatcher by forcing the user to manually deploy containers.
This update removes 'scenario' from test_voltha_xpon.py and puts it in a separate file, which
is then imported by each of these tests.

Change-Id: Ia049ae44686358606939daceab6543e9d455c261
diff --git a/tests/itests/ofagent/test_ofagent_multicontroller_failover.py b/tests/itests/ofagent/test_ofagent_multicontroller_failover.py
index 289a327..e851b64 100644
--- a/tests/itests/ofagent/test_ofagent_multicontroller_failover.py
+++ b/tests/itests/ofagent/test_ofagent_multicontroller_failover.py
@@ -112,7 +112,7 @@
 
     def get_rest_endpoint(self):
         # Retrieve details on the REST entry point
-        rest_endpoint = get_endpoint_from_consul(LOCAL_CONSUL, 'envoy-8443')
+        rest_endpoint = get_endpoint_from_consul(LOCAL_CONSUL, 'voltha-envoy-8443')
 
         # Construct the base_url
         self.base_url = 'https://' + rest_endpoint