Attempt to fix Travis build

celery/tests/worker/test_control.py

@@ -554,7 +554,8 @@ class test_ControlPanel(AppCase):
         consumer.controller.consumer = None
         panel.handle('pool_restart', {'reloader': _reload})
 
-    def test_pool_restart_import_modules(self):
+    @patch('celery.worker.control.logger.debug')
+    def test_pool_restart_import_modules(self, _debug):
         consumer = Consumer(self.app)
         consumer.controller = _WC(app=self.app)
         consumer.controller.consumer = consumer