skins2: remove a comment that proved wrong

scrolling is coded twice in this file, because it contains two class
implementations (CtrlSliderCursor and CtrlSliderBg). Both need this code
since cursor can be on any one of these two controls when scrolling occurs.

modules/gui/skins2/controls/ctrl_slider.cpp

@@ -297,7 +297,6 @@ void CtrlSliderCursor::CmdMove::execute()
 
 void CtrlSliderCursor::CmdScroll::execute()
 {
-    // XXX Two of these in this file, figure out where it really belongs.
     int dir = static_cast<EvtScroll*>(m_pParent->m_pEvt)->getDirection();
     m_pParent->m_rVariable.set( scroll( EvtScroll::kUp == dir,
                                         m_pParent->m_rVariable.get() ) );
@@ -486,7 +485,6 @@ void CtrlSliderBg::handleEvent( EvtGeneric &rEvent )
     }
     else if( rEvent.getAsString().find( "scroll" ) != string::npos )
     {
-        // XXX Two of these in this file, figure out where it really belongs.
         int dir = static_cast<EvtScroll*>(&rEvent)->getDirection();
         m_rVariable.set( scroll( EvtScroll::kUp == dir, m_rVariable.get() ) );
     }