QtMultimedia, QtSerialPort, QtSystems: set some configs enforcing

These are passing.  Make sure they stay that way.

Change-Id: If0da7fc2f0fb4c55b6435519ccd59da3459d33a4
Reviewed-by: Simo Fält <simo.falt@digia.com>
Reviewed-by: Tony Sarajärvi <tony.sarajarvi@digia.com>
Testconfig: Add Enginio credentials file to OpenSuse stages

The stage was missing exporting the path to property file.

Change-Id: I2b4a2377824343c78cd04342b951f66b21c402b7
Reviewed-by: Tony Sarajärvi <tony.sarajarvi@digia.com>