QtIFW

Fix 207cfebb778b.

Obviously there was a problem with the indexOf call. Also once we
omit the -i, the input could be -o or even worse the output path.

Change-Id: I60a970c7e2857195e214cf2441d87468d297a7c2
Reviewed-by: Kai Koehne <kai.koehne@digia.com>
Reviewed-by: Tim Jenssen <tim.jenssen@digia.com>