Adapt to the final DSM API in Qt 5.4.

Change-Id: Iaaf72ee82d7ee0cc288c0a57c87f160cd76e49d2
Reviewed-on: https://codereview.kdab.com/12697
Reviewed-by: Continuous Integration <build@kdab.com>
Reviewed-by: Andreas Holzammer <andreas.holzammer@kdab.com>