Assistant: Fixed build for QT_NO_CURSOR

Change-Id: I5f1f3774ac81ea61406c6ef964fd189051ebe994
Reviewed-by: David Schulz <david.schulz@digia.com>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: Karsten Heimrich <karsten.heimrich@digia.com>