WPrefs: Removed unused Screen argument to the 'Init*' functions

The functions that create the different configuration panels were taking
the screen structure as argument, but it turns out that none of them
actually need it.

We just remove the argument to make code simpler and easier to maintain.

Signed-off-by: Christophe CURIS <christophe.curis@free.fr>

WPrefs.app/WindowHandling.c

@@ -515,7 +515,7 @@ static void undo(_Panel * panel)
 	showData(panel);
 }
 
-Panel *InitWindowHandling(WMScreen * scr, WMWidget * parent)
+Panel *InitWindowHandling(WMWidget *parent)
 {
 	_Panel *panel;