Fix #244

Fix #244

```
alert: [steward] exception diagnostic=Cannot call method 'scan' of undefined
alert: [steward] exception stack=[{"fileName":"/home/pi/steward/steward/devices/devices-climate/climate-samsung-control.js","lineNumber":286,"functionName":"null._onTimeout","typeName":"null","methodName":"_onTimeout","columnNumber":41,"native":false},{"fileName":"[as ontimeout] (timers.js","lineNumber":110,"functionName":"Timer.listOnTimeout","typeName":"Timer","methodName":"listOnTimeout","columnNumber":15,"native":false}]
uncaught exception: TypeError: Cannot call method 'scan' of undefined
```