Refactor: move RulePopulatorUtil into util package, w/ minor fixes

Change-Id: I359040c0e81bfcc0acc32a2299782f442f56a1d3
diff --git a/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackRoutingHandler.java b/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackRoutingHandler.java
index 1d342d2..e2e9327 100644
--- a/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackRoutingHandler.java
+++ b/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackRoutingHandler.java
@@ -59,6 +59,7 @@
 import org.onosproject.openstacknetworking.api.OpenstackRouterEvent;
 import org.onosproject.openstacknetworking.api.OpenstackRouterListener;
 import org.onosproject.openstacknetworking.api.OpenstackRouterService;
+import org.onosproject.openstacknetworking.util.RulePopulatorUtil;
 import org.onosproject.openstacknode.api.OpenstackNode;
 import org.onosproject.openstacknode.api.OpenstackNode.NetworkMode;
 import org.onosproject.openstacknode.api.OpenstackNodeEvent;
@@ -95,7 +96,7 @@
 import static org.onosproject.openstacknetworking.api.Constants.PRIORITY_STATEFUL_SNAT_RULE;
 import static org.onosproject.openstacknetworking.api.Constants.PRIORITY_SWITCHING_RULE;
 import static org.onosproject.openstacknetworking.api.Constants.ROUTING_TABLE;
-import static org.onosproject.openstacknetworking.impl.RulePopulatorUtil.buildExtension;
+import static org.onosproject.openstacknetworking.util.RulePopulatorUtil.buildExtension;
 import static org.onosproject.openstacknode.api.OpenstackNode.NodeType.COMPUTE;
 import static org.onosproject.openstacknode.api.OpenstackNode.NodeType.GATEWAY;