QXcbDrag inherits QBasicDrag which takes care of calling
updateAction() when needed, we don't need to call it explicitly.
Task-number: QTBUG-33057
Change-Id: I754408f74f56de36ace8ffa40a61bd7c64619899
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: Shawn Rutledge <shawn.rutledge@digia.com>