QtIFW

Adjust implementation to match the Unix one and fix unlock.

Add error messages. Fix Unlock, we did use the right argument
but passed on the wrong position(was index 5, should be at 4).

Change-Id: I12564f64997a311a504eaa9b7dd21e75ded8db87
Reviewed-by: Niels Weber <niels.weber@digia.com>
Reviewed-by: Kai Koehne <kai.koehne@theqtcompany.com>