Removed unused done callback of close event listener

[jonasgreen88]

If the listener of a close event accepts a done callback it must be called. Else Node-red will hang, waiting for the callback to be called, while stopping flows where this node is included. In this particular case, without any asynchronous calls in the close listener, there is no need to use the done callback.

[hardillb]

Thanks for spotting that, I probably just added it out of habit when I added the other on close listener. I've got a couple of other updates to do so I'll merge this in with those and push a new version

[jonasgreen88]

You're welcome. Looking forward for the new version of this node!