Adding device driver inheritance mechanism.

Change-Id: I9c883d32ce0c39f961eddd5c4624dc23f794fe4d
diff --git a/core/api/src/test/java/org/onosproject/net/driver/DefaultDriverDataTest.java b/core/api/src/test/java/org/onosproject/net/driver/DefaultDriverDataTest.java
index bf4ad52..006957d 100644
--- a/core/api/src/test/java/org/onosproject/net/driver/DefaultDriverDataTest.java
+++ b/core/api/src/test/java/org/onosproject/net/driver/DefaultDriverDataTest.java
@@ -28,7 +28,7 @@
 
     @Before
     public void setUp() {
-        ddc = new DefaultDriver("foo.bar", "Circus", "lux", "1.2a",
+        ddc = new DefaultDriver("foo.bar", null, "Circus", "lux", "1.2a",
                                 ImmutableMap.of(TestBehaviour.class,
                                                 TestBehaviourImpl.class),
                                 ImmutableMap.of("foo", "bar"));