Crash while editing nodes

[jjamor]

Hi!

I'm using this contrib in a Simatic IOS2000, with Node.JS v6.14.3 and Node-RED 0.16.2.

When I modify any google iot node, Node-RED crashes with following dump:

7 Feb 22:26:17 - TypeError: done is not a function
    at deleteStore (/home/root/.node-red/node_modules/node-red-contrib-google-iot-core/google-iot-core.js:334:17)
    at MqttClient.<anonymous> (/home/root/.node-red/node_modules/node-red-contrib-google-iot-core/google-iot-core.js:342:21)
    at MqttClient.g (events.js:292:16)
    at emitNone (events.js:91:20)
    at MqttClient.emit (events.js:185:7)
    at TLSSocket.f (/home/root/.node-red/node_modules/once/once.js:25:25)
    at TLSSocket.onend (/home/root/.node-red/node_modules/end-of-stream/index.js:36:27)
    at emitNone (events.js:91:20)
    at TLSSocket.emit (events.js:185:7)
    at endReadableNT (_stream_readable.js:978:12)
    at _combinedTickCallback (internal/process/next_tick.js:80:11)
    at process._tickCallback (internal/process/next_tick.js:104:9)

Thanks!