Fix setMouseTracking on QGLWidget

Remove the function altogether. Alternatively we could call the
base class implementation but there is no reason to keep this
confusing, non-virtual override.

Change-Id: Ie8724f7bbc6666fdace7ff777bcde99f3d8a9561
Reviewed-by: Samuel Rødal <samuel.rodal@nokia.com>

src/opengl/qgl.h

@@ -423,8 +423,6 @@ public:
 
     static QImage convertToGLFormat(const QImage& img);
 
-    void setMouseTracking(bool enable);
-
     const QGLColormap & colormap() const;
     void  setColormap(const QGLColormap & map);
 

src/opengl/qgl_qpa.cpp

@@ -336,11 +336,6 @@ void QGLWidgetPrivate::cleanupColormaps()
 {
 }
 
-void QGLWidget::setMouseTracking(bool enable)
-{
-    Q_UNUSED(enable);
-}
-
 bool QGLWidget::event(QEvent *e)
 {
     return QWidget::event(e);