Qt: do not react to right-click to mute volume

This is counter-intuitive.
As asked by etix
(cherry picked from commit 7dab7f2f285f99c78f5aca3802a787f8b369e4c1)
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

modules/gui/qt4/components/controller_widget.cpp

@@ -210,11 +210,13 @@ void SoundWidget::setMuted( bool mute )
 bool SoundWidget::eventFilter( QObject *obj, QEvent *e )
 {
     VLC_UNUSED( obj );
-    if (e->type() == QEvent::MouseButtonPress  )
+    if( e->type() == QEvent::MouseButtonPress )
+    {
+        QMouseEvent *event = static_cast<QMouseEvent*>(e);
+        if( event->button() != Qt::RightButton )
         {
             if( volumeSlider->orientation() ==  Qt::Vertical )
             {
-            QMouseEvent *event = static_cast<QMouseEvent*>(e);
                 showVolumeMenu( event->pos() );
             }
             else
@@ -224,11 +226,9 @@ bool SoundWidget::eventFilter( QObject *obj, QEvent *e )
             e->accept();
             return true;
         }
-    else
-    {
+    }
     e->ignore();
     return false;
-    }
 }
 
 /**