refactor: Replace super(.*self) with Python 3-specific super().

We change all the instances except for the `test_helpers.py`
TimeTrackingCursor monkey-patching, which actually needs to specify
the base class.

zerver/lib/queue.py

@@ -177,7 +177,7 @@ class ExceptionFreeTornadoConnection(pika.adapters.TornadoConnection):
     def _adapter_disconnect(self):
         # type: () -> None
         try:
-            super(ExceptionFreeTornadoConnection, self)._adapter_disconnect()
+            super()._adapter_disconnect()
         except (pika.exceptions.ProbableAuthenticationError,
                 pika.exceptions.ProbableAccessDeniedError,
                 pika.exceptions.IncompatibleProtocolError) as e:
@@ -190,7 +190,7 @@ class TornadoQueueClient(SimpleQueueClient):
     # https://pika.readthedocs.io/en/0.9.8/examples/asynchronous_consumer_example.html
     def __init__(self):
         # type: () -> None
-        super(TornadoQueueClient, self).__init__()
+        super().__init__()
         # Enable rabbitmq heartbeat since TornadoConection can process them
         self.rabbitmq_heartbeat = None
         self._on_open_cbs = []  # type: List[Callable[[], None]]