Qt: reinstate ticks under speed slider

(cherry picked from commit 863692af6914187afd09eba7f84c6e95361ab38f)
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

modules/gui/qt4/components/interface_widgets.cpp

@@ -395,6 +395,7 @@ SpeedControlWidget::SpeedControlWidget( intf_thread_t *_p_i, QWidget *_parent )
     speedSlider->setSizePolicy( sizePolicy );
     speedSlider->setMinimumSize( QSize( 140, 20 ) );
     speedSlider->setOrientation( Qt::Horizontal );
+    speedSlider->setTickPosition( QSlider::TicksBelow );
 
     speedSlider->setRange( -34, 34 );
     speedSlider->setSingleStep( 1 );