[gtk+] assistant: Avoid GdkScreen api

[Matthias Clasen <matthiasc src gnome org>]

commit 0cd864283f1e41821446d5677405b9cde6afff61
Author: Matthias Clasen <mclasen redhat com>
Date:   Mon Oct 30 19:07:14 2017 -0400

    assistant: Avoid GdkScreen api
    
    There is no need at all here to use gtk_settings_get_for_screen.

 gtk/gtkassistant.c |    7 +------
 1 files changed, 1 insertions(+), 6 deletions(-)
---
diff --git a/gtk/gtkassistant.c b/gtk/gtkassistant.c
index 3532d40..e835917 100644
--- a/gtk/gtkassistant.c
+++ b/gtk/gtkassistant.c
@@ -1025,14 +1025,9 @@ on_assistant_last (GtkWidget    *widget,
 static gboolean
 alternative_button_order (GtkAssistant *assistant)
 {
-  GtkSettings *settings;
-  GdkScreen *screen;
   gboolean result;
 
-  screen   = gtk_widget_get_screen (GTK_WIDGET (assistant));
-  settings = gtk_settings_get_for_screen (screen);
-
-  g_object_get (settings,
+  g_object_get (gtk_widget_get_settings (GTK_WIDGET (assistant)),
                 "gtk-alternative-button-order", &result,
                 NULL);
   return result;