[nautilus/gnome-3-20] notebook: fix casting

[Carlos Soriano Sánchez <csoriano src gnome org>]

commit 8dc7020edce6ac190f076c3e90e34338dae45e76
Author: Carlos Soriano <csoriano gnome org>
Date:   Thu Mar 17 16:32:18 2016 +0100

    notebook: fix casting

 src/nautilus-notebook.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/nautilus-notebook.c b/src/nautilus-notebook.c
index ec6aa31..5f8a009 100644
--- a/src/nautilus-notebook.c
+++ b/src/nautilus-notebook.c
@@ -313,7 +313,7 @@ build_tab_label (NautilusNotebook *nb, NautilusWindowSlot *slot)
        gtk_button_set_relief (GTK_BUTTON (close_button),
                               GTK_RELIEF_NONE);
        /* don't allow focus on the close button */
-       gtk_button_set_focus_on_click (GTK_BUTTON (close_button), FALSE);
+       gtk_widget_set_focus_on_click (GTK_WIDGET (close_button), FALSE);
 
        gtk_widget_set_name (close_button, "nautilus-tab-close-button");