Change build to use python 3, minor lint fixes

Change-Id: I3a07c58efb8b676f77426a6ff8cb3e40f13d3f1f
diff --git a/configuration/multicast.rst b/configuration/multicast.rst
index 63fd4c9..a33fe3c 100644
--- a/configuration/multicast.rst
+++ b/configuration/multicast.rst
@@ -199,7 +199,7 @@
 
   .. code-block:: console
 
-      $ curl --user onos:rocks -X DELETE -H 'Accept: application/json' 'http://<controller-ip>:8181/onos/mcast/mcast
+      $ curl --user onos:rocks -X DELETE -H 'Accept: application/json' 'http://<controller-ip>:8181/onos/mcast/mcast'
 
 - Bulk route removal