Fix redis password support. (matrix-org#7401)

We forgot to set the password on the subscriber connection, as well as
not calling super methods for overridden connectionMade/connectionLost
functions.

changelog.d/7401.feature

@@ -0,0 +1 @@
+Add support for running replication over Redis when using workers.

stubs/txredisapi.pyi

@@ -22,7 +22,10 @@ class RedisProtocol:
     def publish(self, channel: str, message: bytes): ...
 
 class SubscriberProtocol:
+    password: Optional[str]
     def subscribe(self, channels: Union[str, List[str]]): ...
+    def connectionMade(self): ...
+    def connectionLost(self, reason): ...
 
 def lazyConnection(
     host: str = ...,

synapse/replication/tcp/redis.py

@@ -61,6 +61,7 @@ class RedisSubscriber(txredisapi.SubscriberProtocol, AbstractConnection):
     outbound_redis_connection = None  # type: txredisapi.RedisProtocol
 
     def connectionMade(self):
+        super().connectionMade()
         logger.info("Connected to redis instance")
         self.subscribe(self.stream_name)
         self.send_command(ReplicateCommand())
@@ -119,6 +120,7 @@ async def handle_command(self, cmd: Command):
             logger.warning("Unhandled command: %r", cmd)
 
     def connectionLost(self, reason):
+        super().connectionLost(reason)
         logger.info("Lost connection to redis instance")
         self.handler.lost_connection(self)
 
@@ -189,5 +191,6 @@ def buildProtocol(self, addr):
         p.handler = self.handler
         p.outbound_redis_connection = self.outbound_redis_connection
         p.stream_name = self.stream_name
+        p.password = self.password
 
         return p