Adding Multisct traffic drop for un-programmed trees

Change-Id: If9615db254f69141d8d6f0da3e0b7ce7d154bd6b
diff --git a/apps/segmentrouting/app/src/main/java/org/onosproject/segmentrouting/SegmentRoutingManager.java b/apps/segmentrouting/app/src/main/java/org/onosproject/segmentrouting/SegmentRoutingManager.java
index 5b520b9..49d2f37 100644
--- a/apps/segmentrouting/app/src/main/java/org/onosproject/segmentrouting/SegmentRoutingManager.java
+++ b/apps/segmentrouting/app/src/main/java/org/onosproject/segmentrouting/SegmentRoutingManager.java
@@ -1299,6 +1299,7 @@
             DefaultGroupHandler groupHandler = groupHandlerMap.get(deviceId);
             groupHandler.createGroupsFromVlanConfig();
             routingRulePopulator.populateSubnetBroadcastRule(deviceId);
+            mcastHandler.dropUnprogrammedTrees(deviceId);
         }
 
         appCfgHandler.init(deviceId);