Fix some compilation warnings.

Change-Id: I7d9b28ac32ac84e3ed6ab2255e1db6245be14c77
diff --git a/src/main/java/net/onrc/onos/core/packet/Ethernet.java b/src/main/java/net/onrc/onos/core/packet/Ethernet.java
index 089a481..aab5e7b 100644
--- a/src/main/java/net/onrc/onos/core/packet/Ethernet.java
+++ b/src/main/java/net/onrc/onos/core/packet/Ethernet.java
@@ -392,7 +392,7 @@
 
         StringBuffer sb = new StringBuffer("\n");
 
-        IPacket pkt = (IPacket) this.getPayload();
+        IPacket pkt = this.getPayload();
 
         if (pkt instanceof ARP) {
             sb.append("arp");
@@ -447,7 +447,7 @@
             sb.append("\nnw_proto: ");
             sb.append(p.getProtocol());
 
-            IPacket payload = (IPacket) pkt.getPayload();
+            IPacket payload = pkt.getPayload();
             if (payload instanceof TCP) {
                 sb.append("\ntp_src: ");
                 sb.append(((TCP) payload).getSourcePort());