[gtk] Fix a compiler warning

[Matthias Clasen <matthiasc src gnome org>]

commit 825b48911b091528118d8cd207932b73c69f751e
Author: Matthias Clasen <mclasen redhat com>
Date:   Sun May 19 16:45:23 2019 -0400

    Fix a compiler warning

 gtk/gtkapplicationwindow.c | 1 -
 1 file changed, 1 deletion(-)
---
diff --git a/gtk/gtkapplicationwindow.c b/gtk/gtkapplicationwindow.c
index 066233a6c6..923a1137b9 100644
--- a/gtk/gtkapplicationwindow.c
+++ b/gtk/gtkapplicationwindow.c
@@ -751,7 +751,6 @@ gtk_application_window_set_property (GObject      *object,
                                      GParamSpec   *pspec)
 {
   GtkApplicationWindow *window = GTK_APPLICATION_WINDOW (object);
-  GtkApplicationWindowPrivate *priv = gtk_application_window_get_instance_private (window);
 
   switch (prop_id)
     {