[refactor] Add mosquitto to travis
[refactor] Add mosquitto to travis

mgranberry/ttn,LoRaWanSoFa/ttn,TheThingsNetwork/ttn,jvanmalder/ttn,LoRaWanSoFa/ttn,mgranberry/ttn,jvanmalder/ttn,jvanmalder/ttn,mgranberry/ttn,TheThingsNetwork/ttn,TheThingsNetwork/ttn