Fixed ARP reply

Change-Id: I04f2d9ef727c37481beeb8569634b8a7edb5f271
diff --git a/apps/cordvtn/src/main/java/org/onosproject/cordvtn/CordVtnArpProxy.java b/apps/cordvtn/src/main/java/org/onosproject/cordvtn/CordVtnArpProxy.java
index 5f444e0..feee5a7 100644
--- a/apps/cordvtn/src/main/java/org/onosproject/cordvtn/CordVtnArpProxy.java
+++ b/apps/cordvtn/src/main/java/org/onosproject/cordvtn/CordVtnArpProxy.java
@@ -143,7 +143,7 @@
 
         Ethernet ethReply = ARP.buildArpReply(
                 targetIp,
-                gatewayMac,
+                macAddr,
                 ethPacket);
 
         TrafficTreatment treatment = DefaultTrafficTreatment.builder()