Remove outdated x11 overrides (#355)

Author: lenemter

overrides/default-settings.gschema.override.in

@@ -134,7 +134,7 @@ eject-static=[]
 idle-dim=false
 
 [org.gnome.settings-daemon.plugins.xsettings:Pantheon]
-overrides={'Gtk/DialogsUseHeader': <0>, 'Gtk/EnablePrimaryPaste': <0>, 'Gtk/ShellShowsAppMenu': <0>, 'Gtk/DecorationLayout': <'close:menu,maximize'>,'Gtk/ShowUnicodeMenu': <0>}
+overrides={'Gtk/DialogsUseHeader': <0>}
 
 [org.gnome.system.location:Pantheon]
 enabled=true