fixed a few timer warning

tests/test_vertex2.py

@@ -65,7 +65,7 @@ class PowerTests(unittest.TestCase):
         connection.shutdown.assert_called_once_with(socket.SHUT_RDWR)
         app.turn_off.assert_called_once_with('switch.vertex2')
         self.assertFalse(app._vertex2_powered())
-        app.cancel_timer.assert_called_once_with('timer')
+        app.cancel_timer.assert_called_once_with('timer', silent=True)
         self.assertIsNone(app._command_processing_deadline)
         app.command_processing_sensor.set_state.assert_called_once_with(state='off')
         app.unreachable_sensor.set_state.assert_called_once_with(state='off')
@@ -486,8 +486,8 @@ class SpamSensorTests(unittest.TestCase):
         self.assertTrue(app._interrupt_stop.is_set())
         self.assertIsNone(app._spam_timer)
         self.assertIsNone(app._spam_deadline)
-        app.cancel_timer.assert_any_call('spam_timer')
-        app.cancel_timer.assert_any_call('timer')
+        app.cancel_timer.assert_any_call('spam_timer', silent=True)
+        app.cancel_timer.assert_any_call('timer', silent=True)
         app.no_signal_spam_sensor.set_state.assert_not_called()
         # An already queued expiry callback must also leave the state alone.
         app._expire_no_signal_spam({'deadline': 110})