[libhandy] preferences-group: Fix a leak in dispose()

[Adrien Plazas <aplazas src gnome org>]

commit b98974f06ce4773efd5bf54d728cbd780d3d1254
Author: Alexander Mikhaylenko <alexm gnome org>
Date:   Thu Dec 17 13:06:51 2020 +0500

    preferences-group: Fix a leak in dispose()
    
    Long ago we were subclassing GtkBox and all these widgets were internal.
    
    Since then we switched to subclassing GtkBin and including a box, and never
    updated this function, causing a leak.

 src/hdy-preferences-group.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)
---
diff --git a/src/hdy-preferences-group.c b/src/hdy-preferences-group.c
index 80006274..92b2e3b7 100644
--- a/src/hdy-preferences-group.c
+++ b/src/hdy-preferences-group.c
@@ -180,12 +180,13 @@ hdy_preferences_group_dispose (GObject *object)
 
   /*
    * Since we overload forall(), the inherited destroy() won't work as normal.
-   * Remove internal widgets ourself.
+   * Remove internal widgets ourselves.
    */
-  g_clear_pointer ((GtkWidget **) &priv->description, gtk_widget_destroy);
-  g_clear_pointer ((GtkWidget **) &priv->listbox, gtk_widget_destroy);
-  g_clear_pointer ((GtkWidget **) &priv->listbox_box, gtk_widget_destroy);
-  g_clear_pointer ((GtkWidget **) &priv->title, gtk_widget_destroy);
+  g_clear_pointer ((GtkWidget **) &priv->box, gtk_widget_destroy);
+  priv->description = NULL;
+  priv->listbox = NULL;
+  priv->listbox_box = NULL;
+  priv->title = NULL;
 
   G_OBJECT_CLASS (hdy_preferences_group_parent_class)->dispose (object);
 }