Qt: fix possible double-free on quit with simple volume widget

modules/gui/qt4/components/controller_widget.cpp

@@ -71,7 +71,7 @@ SoundWidget::SoundWidget( QWidget *_parent, intf_thread_t * _p_intf,
         /* Special view, click on button shows the slider */
         b_shiny = false;
 
-        volumeControlWidget = new QFrame;
+        volumeControlWidget = new QFrame( this );
         subLayout = new QVBoxLayout( volumeControlWidget );
         subLayout->setContentsMargins( 4, 4, 4, 4 );
         volumeMenu = new QMenu( this );
@@ -122,12 +122,6 @@ SoundWidget::SoundWidget( QWidget *_parent, intf_thread_t * _p_intf,
     CONNECT( THEMIM, soundMuteChanged( bool ), this, updateMuteStatus( bool ) );
 }
 
-SoundWidget::~SoundWidget()
-{
-    delete volumeSlider;
-    delete volumeControlWidget;
-}
-
 void SoundWidget::refreshLabels()
 {
     int i_sliderVolume = volumeSlider->value();

modules/gui/qt4/components/controller_widget.hpp

@@ -99,7 +99,6 @@ class SoundWidget : public QWidget
 public:
     SoundWidget( QWidget *parent, intf_thread_t  *_p_i, bool,
                  bool b_special = false );
-    virtual ~SoundWidget();
     void setMuted( bool );
 
 protected: