header bar: Don't leave a dangling pointer

This might be the cause for some crashes, like
https://bugzilla.redhat.com/show_bug.cgi?id=1264558

diff --git a/gtk/gtkheaderbar.c b/gtk/gtkheaderbar.c
index 9e81d3168153505ebc97985fad1a7f1937003c4a..7589e1faa80e7d6e8c4328e441f1d5d5ebde97b9 100644 (file)
--- a/gtk/gtkheaderbar.c
+++ b/gtk/gtkheaderbar.c
@@ -299,6 +299,8 @@ _gtk_header_bar_update_window_buttons (GtkHeaderBar *bar)
       priv->titlebar_end_separator = NULL;
     }
 
+  priv->titlebar_icon = NULL;
+
   if (!priv->shows_wm_decorations)
     return;