Application stop/start

[hairyhum]

When rabbitmq_web_mqtt application is being stopped, it cannot be restarted because ranch listener is still running.

{could_not_start,rabbitmq_web_mqtt,
           {{badmatch,{error,{already_started,<10252.494.0>}}},
            [{rabbit_web_mqtt_app,mqtt_init,0,
                 [{file,"src/rabbit_web_mqtt_app.erl"},{line,60}]},
             {rabbit_web_mqtt_app,start,2,
                 [{file,"src/rabbit_web_mqtt_app.erl"},{line,31}]},
             {application_master,start_it_old,4,
                 [{file,"application_master.erl"},{line,273}]}]}}

[michaelklishin]

The PR is against master. Is this intentional? any reason why this cannot be done in stable, which this repo now has?

[hairyhum]

It was meant to fix master tests, but it's better go to stable.