Refactor: simplify setoutput port to controller using punt method

Change-Id: Ifb906fb40f96fb1d7b3565f5921fcdc4fea02ad0
diff --git a/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackSwitchingDhcpHandler.java b/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackSwitchingDhcpHandler.java
index 5e2947f..3602275 100644
--- a/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackSwitchingDhcpHandler.java
+++ b/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackSwitchingDhcpHandler.java
@@ -38,7 +38,6 @@
 import org.onosproject.core.ApplicationId;
 import org.onosproject.core.CoreService;
 import org.onosproject.net.ConnectPoint;
-import org.onosproject.net.PortNumber;
 import org.onosproject.net.flow.DefaultTrafficSelector;
 import org.onosproject.net.flow.DefaultTrafficTreatment;
 import org.onosproject.net.flow.TrafficSelector;
@@ -178,7 +177,7 @@
                 .build();
 
         TrafficTreatment treatment = DefaultTrafficTreatment.builder()
-                .setOutput(PortNumber.CONTROLLER)
+                .punt()
                 .build();
 
         osNodeService.completeNodes(COMPUTE).forEach(node -> {