QtIFW

Refine server starting/stopping code.

If we can't connect, the server is most likely not running.
Also send an acknowledgment that we are going to shutdown.

Change-Id: I1a06b0ea5b5bdeb736042ca8b49508b6a4fd90b8
Reviewed-by: Niels Weber <niels.weber@theqtcompany.com>
Reviewed-by: Kai Koehne <kai.koehne@theqtcompany.com>