Support Kryo serialization for intent related types

- Implement the protected constructors
- Register the types in KryoFactory

Change-Id: I14214ed1703a8e4b3145625732c74600fc0aba06
diff --git a/src/main/java/net/onrc/onos/api/newintent/IntentId.java b/src/main/java/net/onrc/onos/api/newintent/IntentId.java
index b7cdb01..ebe1b45 100644
--- a/src/main/java/net/onrc/onos/api/newintent/IntentId.java
+++ b/src/main/java/net/onrc/onos/api/newintent/IntentId.java
@@ -27,6 +27,12 @@
         return new IntentId(id);
     }
 
+    /**
+     * Constructor for serializer.
+     */
+    protected IntentId() {
+        this.id = 0;
+    }
 
     /**
      * Constructs the ID corresponding to a given long value.