Missing break in case QEvent::WindowStateChange.

The missing break causes state change event handling to fall through
to tablet event handling, which is clearly wrong.

Change-Id: If19d7b3f794b3614961b9e79952331b0ede1fba1
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>

src/gui/kernel/qwindow.cpp

@@ -1707,6 +1707,7 @@ bool QWindow::event(QEvent *ev)
     case QEvent::WindowStateChange: {
         Q_D(QWindow);
         emit windowStateChanged(d->windowState);
+        break;
     }
 
 #ifndef QT_NO_TABLETEVENT