[gnome-builder] workbench: change icon-name on image, not button

[Christian Hergert <chergert src gnome org>]

commit 00657fe7f13d091e475afb72b70a272bf65dbfea
Author: Christian Hergert <chergert redhat com>
Date:   Thu Dec 14 02:39:05 2017 -0800

    workbench: change icon-name on image, not button

 src/libide/workbench/ide-workbench-header-bar.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/libide/workbench/ide-workbench-header-bar.c b/src/libide/workbench/ide-workbench-header-bar.c
index f3c9988..2bb358c 100644
--- a/src/libide/workbench/ide-workbench-header-bar.c
+++ b/src/libide/workbench/ide-workbench-header-bar.c
@@ -262,7 +262,7 @@ _ide_workbench_header_bar_set_fullscreen (IdeWorkbenchHeaderBar *self,
 
   g_return_if_fail (IDE_IS_WORKBENCH_HEADER_BAR (self));
 
-  g_object_set (priv->fullscreen_button,
+  g_object_set (priv->fullscreen_image,
                 "icon-name", icon_names[!!fullscreen],
                 NULL);
   gtk_header_bar_set_show_close_button (GTK_HEADER_BAR (self), fullscreen == FALSE);