Client hangs on retry

[mcuadros]

The reconnect clients hang on reconnect when it resubscribing to a topic even if is QoS0: https://github.com/at-wat/mqtt-go/blob/78fc5497cbe7e1d361f5a8ed1f53b3f7db283190/retryclient.go#L47 It doesn't have any default value and it's used on the subscription to the topics: https://github.com/at-wat/mqtt-go/blob/master/retryclient.go#L361

So sorry but I don't have any sample code but till I configured the ResponseTimeout, my project was hanging after a few hours of working. Since I set up the timeout it's not happing anymore.