fix igmp-query packet outs for the olt

Change-Id: Ic3daf5e286f70e68eb6d91bdffa1a498aa562668
diff --git a/src/main/java/org/onosproject/igmp/IgmpSnoop.java b/src/main/java/org/onosproject/igmp/IgmpSnoop.java
index 58e5826..4a3fc94 100644
--- a/src/main/java/org/onosproject/igmp/IgmpSnoop.java
+++ b/src/main/java/org/onosproject/igmp/IgmpSnoop.java
@@ -368,6 +368,8 @@
 
         eth.setPayload(ip);
 
+        eth.setPad(true);
+
         return ByteBuffer.wrap(eth.serialize());
     }