gscreen: remove deprecated use of GtkLabel constructor

In detail:
PyGTKDeprecationWarning: Using positional arguments with the GObject constructor has been deprecated. Please specify keyword(s) for "label" or use a class specific constructor.

src/emc/usr_intf/gscreen/gscreen.py

@@ -3924,7 +3924,7 @@ def restart_dialog_return(self,widget,result,calc):
     def _dynamic_tab(self, widget, text):
         s = Gtk.Socket()
         try:
-            widget.append_page(s, Gtk.Label(" " + text + " "))
+            widget.append_page(s, Gtk.Label.new(" " + text + " "))
         except:
             try:
                 widget.pack_end(s,True,True,0)