Revert "set auto_delete=false for QoS1 subscriptions"

This reverts commit d26b6e1c91.

See #37, the behaviour prior to the change in #25
was correct, per discussion with MQTT plugin users.

Note that the combination of QoS 1 and Clean Session makes
no sense: this QoS 0 is meant to be used for transient connections.

References #25, #30.

deps/rabbitmq_mqtt/src/rabbit_mqtt_processor.erl

@@ -429,7 +429,7 @@ ensure_queue(Qos, #proc_state{ channels      = {Channel, _},
                 {QueueQ1,
                  #'queue.declare'{ queue       = QueueQ1,
                                    durable     = true,
-                                   auto_delete = false,
+                                   auto_delete = CleanSess,
                                    arguments   = Qos1Args },
                  #'basic.consume'{ queue  = QueueQ1,
                                    no_ack = false }};