[refactor] remove typo in handler HandleDown
[refactor] remove typo in handler HandleDown

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