[CORD-2906] dhcpv6 server ack pkt needs to set VID according to client vid

Change-Id: I21d651859e8525d7fbd826921ac7352f1f13fec9
diff --git a/apps/dhcprelay/src/main/java/org/onosproject/dhcprelay/Dhcp6HandlerImpl.java b/apps/dhcprelay/src/main/java/org/onosproject/dhcprelay/Dhcp6HandlerImpl.java
index e329063..4d1be53 100644
--- a/apps/dhcprelay/src/main/java/org/onosproject/dhcprelay/Dhcp6HandlerImpl.java
+++ b/apps/dhcprelay/src/main/java/org/onosproject/dhcprelay/Dhcp6HandlerImpl.java
@@ -1228,6 +1228,8 @@
             dhcpRelayCountersStore.incrementCounter(gCount, DhcpRelayCounters.NO_MATCHING_INTF);
             return null;
         }
+        etherReply.setVlanID(vlanIdInUse.toShort());
+
         MacAddress relayAgentMac = clientInterface.mac();
         if (relayAgentMac == null) {
             log.warn("Can not get client interface mac, abort packet..");