Refactor: Avoid using ternary operator. Remove unnecessary casting.

	* Apply suggestion in #2192 to previous implemented classes

Change-Id: I271d64202dd43968825600cd9afc49eb400371bf
diff --git a/utils/misc/src/main/java/org/onlab/packet/ICMP6.java b/utils/misc/src/main/java/org/onlab/packet/ICMP6.java
index 13deab2..bb4f204 100644
--- a/utils/misc/src/main/java/org/onlab/packet/ICMP6.java
+++ b/utils/misc/src/main/java/org/onlab/packet/ICMP6.java
@@ -121,7 +121,10 @@
             payloadData = this.payload.serialize();
         }
 
-        int payloadLength = payloadData == null ? 0 : (short) payloadData.length;
+        int payloadLength = 0;
+        if (payloadData != null) {
+            payloadLength = payloadData.length;
+        }
 
         final byte[] data = new byte[HEADER_LENGTH + payloadLength];
         final ByteBuffer bb = ByteBuffer.wrap(data);