Check doNotFlushFlows flag in initilizeFlowRules

Change-Id: I7ce74d5194a1d20f55af11749f11f9983308bb71
diff --git a/apps/openstackswitching/app/src/main/java/org/onosproject/openstackswitching/OpenstackSwitchingManager.java b/apps/openstackswitching/app/src/main/java/org/onosproject/openstackswitching/OpenstackSwitchingManager.java
index 3d81703..5635f7b 100644
--- a/apps/openstackswitching/app/src/main/java/org/onosproject/openstackswitching/OpenstackSwitchingManager.java
+++ b/apps/openstackswitching/app/src/main/java/org/onosproject/openstackswitching/OpenstackSwitchingManager.java
@@ -278,7 +278,9 @@
                             .forEach(vmPort -> {
                                         OpenstackPort osPort = rulePopulator.openstackPort(vmPort);
                                         if (osPort != null) {
-                                            rulePopulator.populateSwitchingRules(device, vmPort);
+                                            if (!doNotPushFlows) {
+                                                rulePopulator.populateSwitchingRules(device, vmPort);
+                                            }
                                             registerDhcpInfo(osPort);
                                         } else {
                                             log.warn("No openstackPort information for port {}", vmPort);