Call ext_manager.delete_port on port removal

This patch updates OVSNeutronAgent to call ext_manager.delete_port
when the port is removed (similar to how CommonAgentLoop does).

Otherwise the QoS PortPolicyMap is not properly updated on port
removal and QoS extension will not apply policies if that port is
later reused by a VM on the same node (unless the agent is restarted).

Change-Id: I306c496985a550176d0ddc6eb33a4a4d351acb55
Closes-Bug: #1515533

neutron/plugins/ml2/drivers/openvswitch/agent/ovs_neutron_agent.py

@@ -1577,6 +1577,7 @@ def treat_devices_removed(self, devices):
         failed_devices = set(devices_down.get('failed_devices_down'))
         LOG.debug("Port removal failed for %s", failed_devices)
         for device in devices:
+            self.ext_manager.delete_port(self.context, {'port_id': device})
             self.port_unbound(device)
         return failed_devices
 

neutron/tests/unit/plugins/ml2/drivers/openvswitch/agent/test_ovs_neutron_agent.py

@@ -865,6 +865,21 @@ def test_treat_devices_removed_failed_devices(self):
             failed_devices['removed'] = self.agent.treat_devices_removed([{}])
             self.assertEqual(set([dev_mock]), failed_devices.get('removed'))
 
+    def test_treat_devices_removed_ext_delete_port(self):
+        port_id = 'fake-id'
+
+        m_delete = mock.patch.object(self.agent.ext_manager, 'delete_port')
+        m_rpc = mock.patch.object(self.agent.plugin_rpc, 'update_device_list',
+                                  return_value={'devices_up': [],
+                                                'devices_down': [],
+                                                'failed_devices_up': [],
+                                                'failed_devices_down': []})
+        m_unbound = mock.patch.object(self.agent, 'port_unbound')
+
+        with m_delete as delete, m_rpc, m_unbound:
+            self.agent.treat_devices_removed([port_id])
+            delete.assert_called_with(mock.ANY, {'port_id': port_id})
+
     def test_bind_port_with_missing_network(self):
         vif_port = mock.Mock()
         vif_port.name.return_value = 'port'