Updating MatchAction objects with no-arg constructors and registering them with Kryo

Change-Id: I3512b2e99624c3f496d786ea99133b385a35094e
diff --git a/src/main/java/net/onrc/onos/core/matchaction/MatchAction.java b/src/main/java/net/onrc/onos/core/matchaction/MatchAction.java
index 5f7d9fb..fdf1fc7 100644
--- a/src/main/java/net/onrc/onos/core/matchaction/MatchAction.java
+++ b/src/main/java/net/onrc/onos/core/matchaction/MatchAction.java
@@ -32,6 +32,16 @@
     }
 
     /**
+     * no-arg constructor for Kryo.
+     */
+    protected MatchAction() {
+        id = null;
+        port = null;
+        match = null;
+        actions = null;
+    }
+
+    /**
      * Constructor. TEMPORARY
      *
      * @param id ID for this MatchAction object