(qt4) fix displaying of tvtelx-transparent

The source code in components/interface_widgets.cpp referred to the tvtelx-transparent image as telexTransparent->setIcon( QIcon( ":/tvtelx-transparent" ) ), while the vlc.qrc resource file referred to it as "tvtelx-trans".

modules/gui/qt4/components/interface_widgets.cpp

@@ -829,7 +829,7 @@ void ControlsWidget::toggleTeletextTransparency()
     }
     else
     {
-        telexTransparent->setIcon( QIcon( ":/tvtelx-transparent" ) );
+        telexTransparent->setIcon( QIcon( ":/tvtelx-trans" ) );
         telexTransparent->setToolTip( qtr( "Transparent" ) );
         b_telexTransparent = true;
     }