OPENSTACK-2959: add device_owner for update_port_on_subnet

add device_owner for update_port_on_subnet, in order to reset
device_owner for selfip port (if vtep/mac changed) and snat ip
port.

Author: zhang-shengping

f5lbaasdriver/v2/bigip/plugin_rpc.py

@@ -632,7 +632,8 @@ def update_port_on_subnet(
         self, context, port_id, port_name=None,
         subnet_id=None, mac_address=None,
         fixed_address_count=0,
-        binding_profile=None
+        binding_profile=None,
+        device_owner=None
     ):
         port = {'port': {}}
 
@@ -651,6 +652,9 @@ def update_port_on_subnet(
         if binding_profile is not None:
             port['port']['binding:profile'] = binding_profile
 
+        if device_owner is not None:
+            port['port']['device_owner'] = device_owner
+
         if not port['port']:
             return