ONOS-3403 Fix bug of onosfw can't get extension driver.

Change-Id: I1ab614f7f0d521c1935fb0e0db31018fd944c5ae
diff --git a/drivers/src/main/resources/onos-drivers.xml b/drivers/src/main/resources/onos-drivers.xml
index 9810781..0349e1c 100644
--- a/drivers/src/main/resources/onos-drivers.xml
+++ b/drivers/src/main/resources/onos-drivers.xml
@@ -131,7 +131,7 @@
         <behaviour api="org.onosproject.openflow.controller.driver.OpenFlowSwitchDriver"
                    impl="org.onosproject.driver.handshaker.CalientFiberSwitchHandshaker"/>
     </driver>
-    <driver name="onosfw" extends="default"
+    <driver name="onosfw" extends="ovs"
             manufacturer="" hwVersion="" swVersion="">
         <behaviour api="org.onosproject.net.behaviour.Pipeliner"
                    impl="org.onosproject.driver.pipeline.OpenVSwitchPipeline"/>