Qt: frame around speed selector is unnecessary

Or just ugly in some themes

(cherry picked from commit 776ea95fd86732ac1fc891733d1e25e165f50196)
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

modules/gui/qt4/components/interface_widgets.cpp

@@ -483,9 +483,6 @@ SpeedLabel::SpeedLabel( intf_thread_t *_p_intf, QWidget *parent )
     DCONNECT( THEMIM, inputChanged( ),
               speedControl, activateOnState() );
 
-    setFrameStyle( QFrame::StyledPanel | QFrame::Raised );
-    setLineWidth( 1 );
-
     setRate( var_InheritFloat( THEPL, "rate" ) );
 }