All neutron plugins should now use LibvirtGenericVIFDriver

Change-Id: I70015ae55fe6db9c6c4663a8d021fe9cfe2eddcf
diff --git a/lib/neutron_plugins/ovs_base b/lib/neutron_plugins/ovs_base
index 1214f3b..89db29d 100644
--- a/lib/neutron_plugins/ovs_base
+++ b/lib/neutron_plugins/ovs_base
@@ -73,7 +73,7 @@
 }
 
 function _neutron_ovs_base_configure_nova_vif_driver() {
-    NOVA_VIF_DRIVER=${NOVA_VIF_DRIVER:-"nova.virt.libvirt.vif.LibvirtGenericVIFDriver"}
+    :
 }
 
 # Restore xtrace