Use ArrayUtils.clone() to clone byte[] arrays.

Using ArrayUtils.clone() simplifies the code, because it handles
null arrays.

Change-Id: I434856c5a9713759a642dd32a7ca8dfafb136047
diff --git a/src/main/java/net/onrc/onos/core/packet/TCP.java b/src/main/java/net/onrc/onos/core/packet/TCP.java
index def194c..6b6c355 100644
--- a/src/main/java/net/onrc/onos/core/packet/TCP.java
+++ b/src/main/java/net/onrc/onos/core/packet/TCP.java
@@ -20,6 +20,8 @@
 import java.nio.ByteBuffer;
 import java.util.Arrays;
 
+import org.apache.commons.lang.ArrayUtils;
+
 /**
  * @author shudong.zhou@bigswitch.com
  */
@@ -142,19 +144,15 @@
     }
 
     public byte[] getOptions() {
-        if (this.options == null) {
-            return null;
-        }
-        return this.options.clone();
+        return ArrayUtils.clone(this.options);
     }
 
     public TCP setOptions(final byte[] options) {
-        if (options == null) {
-            this.options = null;
+        this.options = ArrayUtils.clone(options);
+        if (this.options == null) {
             this.dataOffset = 0;
         } else {
-            this.options = options.clone();
-            this.dataOffset = (byte) ((20 + options.length + 3) >> 2);
+            this.dataOffset = (byte) ((20 + this.options.length + 3) >> 2);
         }
         return this;
     }