BugFix: Add default constructor to OnosInstanceId

- Adding default constructor to make it Kryo deserializable.

Change-Id: Ic17926d88b30853620ab0c1c8d18f053793771c0
diff --git a/src/main/java/net/onrc/onos/core/util/OnosInstanceId.java b/src/main/java/net/onrc/onos/core/util/OnosInstanceId.java
index 34e370a..61b0751 100644
--- a/src/main/java/net/onrc/onos/core/util/OnosInstanceId.java
+++ b/src/main/java/net/onrc/onos/core/util/OnosInstanceId.java
@@ -12,6 +12,14 @@
     private final String id;
 
     /**
+     * Default constructor for serializer.
+     */
+    @Deprecated
+    protected OnosInstanceId() {
+        id = "(should never see this)";
+    }
+
+    /**
      * Constructor from a string value.
      *
      * @param id the value to use.
diff --git a/src/test/java/net/onrc/onos/core/util/serializers/KryoFactoryTest.java b/src/test/java/net/onrc/onos/core/util/serializers/KryoFactoryTest.java
index 95b1ca2..9431cfe 100644
--- a/src/test/java/net/onrc/onos/core/util/serializers/KryoFactoryTest.java
+++ b/src/test/java/net/onrc/onos/core/util/serializers/KryoFactoryTest.java
@@ -16,6 +16,7 @@
 import net.onrc.onos.core.topology.TopologyEvent;
 import net.onrc.onos.core.topology.SwitchEvent;
 import net.onrc.onos.core.util.Dpid;
+import net.onrc.onos.core.util.OnosInstanceId;
 import net.onrc.onos.core.util.PortNumber;
 import net.onrc.onos.core.util.SwitchPort;
 
@@ -229,6 +230,15 @@
             assertEquals(27, result.size);
         }
 
+        { // CHECKSTYLE IGNORE THIS LINE
+            OnosInstanceId id = new OnosInstanceId("Some_Instance_Name");
+
+            Result result = benchType(id, EqualityCheck.EQUALS);
+            results.add(result);
+            // update me if serialized form is expected to change
+            assertEquals(21, result.size);
+        }
+
         // TODO Add registered classes we still use.