CLOUDSTACK-9094: Multiple threads are being used to collect the stats from the same VR

Same thread is being intialised by two managers, VirtualNetworkApplianceManager and VpcVirtualNetworkApplianceManager

server/src/com/cloud/network/router/VpcVirtualNetworkApplianceManagerImpl.java

@@ -684,6 +684,16 @@ public class VpcVirtualNetworkApplianceManagerImpl extends VirtualNetworkApplian
         return _routerDao.listByVpcId(vpcId);
     }
 
+    @Override
+    public boolean start() {
+        return true;
+    }
+
+    @Override
+    public boolean stop() {
+        return true;
+    }
+
     @Override
     public boolean startRemoteAccessVpn(final RemoteAccessVpn vpn, final VirtualRouter router) throws ResourceUnavailableException {
         if (router.getState() != State.Running) {