Fix: do not uninstall group table rules if flag is unset

Change-Id: I1e04cedd97271fdfdc8b0533421c7a5b1e109bc3
diff --git a/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackSecurityGroupHandler.java b/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackSecurityGroupHandler.java
index 140facf..9179a3a 100644
--- a/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackSecurityGroupHandler.java
+++ b/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackSecurityGroupHandler.java
@@ -1107,7 +1107,7 @@
 
         @Override
         public boolean isRelevant(OpenstackNodeEvent event) {
-            return event.subject().type() == COMPUTE;
+            return event.subject().type() == COMPUTE && useSecurityGroup;
         }
 
         private boolean isRelevantHelper() {