Test: Support for ONOS cluster mode startup with --onos-instances option to cord-test.py setup.
Changes to igmpTest to do a rover join test with support for parallel test runs across multiple containers.

Change-Id: If9c01df4c2ff5f2f6961eef9ff6fa865abb29b53
diff --git a/src/test/utils/CordTestServer.py b/src/test/utils/CordTestServer.py
index 47b84e3..7b60620 100644
--- a/src/test/utils/CordTestServer.py
+++ b/src/test/utils/CordTestServer.py
@@ -53,7 +53,10 @@
         if self.onos_cord:
             self.onos_cord.start(restart = True, network_cfg = config)
         else:
-            Onos(restart = True, network_cfg = config, image = Onos.IMAGE, tag = Onos.TAG)
+            if Onos.cluster_mode is True:
+                Onos.restart_cluster(network_cfg = config)
+            else:
+                Onos(restart = True, network_cfg = config, image = Onos.IMAGE, tag = Onos.TAG)
         return 'DONE'
 
     def restart_onos(self, kwargs):