Fix for wdtStart flag

[pedzed]

Closes #19

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[jpmeijers]

The suggestion that this is a bug makes sense. I however find it strange that no one else complained about this. Let's at least test this before merging in.

[johanstokking]

I'm quite sure this is a valid bug.

@pedzed did you test this with going on/off/on/off?

[loganmc10]

Is there something I can do to help test this? It seems like a pretty obvious typo

[johanstokking]

Released in https://github.com/TheThingsNetwork/arduino-node-lib/releases/tag/v2.0.8