Change OFPacketIn.MINIMUM_LENGTH from an int to a short....

Change OFPacketIn.MINIMUM_LENGTH from an int to a short. OFPacketIn.setTotalLength() expects a short.

src/main/java/org/openflow/protocol/OFPacketIn.java

@@ -30,7 +30,7 @@ import org.openflow.util.U8;
  * @author David Erickson (daviderickson@cs.stanford.edu) - Feb 8, 2010
  */
 public class OFPacketIn extends OFMessage {
-    public static int MINIMUM_LENGTH = 18;
+    public static short MINIMUM_LENGTH = 18;
 
     public enum OFPacketInReason {
         NO_MATCH, ACTION