[libdazzle] tree: force clear model upon tree destruction

[Christian Hergert <chergert src gnome org>]

commit 6e1d6197b0f670887025dafdde03dde73e91b185
Author: Christian Hergert <chergert redhat com>
Date:   Mon Jul 30 20:19:04 2018 -0700

    tree: force clear model upon tree destruction
    
    This helps us ensure that the tree is destroyed during cleanup which makes
    tracking leaks easier.

 src/tree/dzl-tree.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)
---
diff --git a/src/tree/dzl-tree.c b/src/tree/dzl-tree.c
index 969a195..532b074 100644
--- a/src/tree/dzl-tree.c
+++ b/src/tree/dzl-tree.c
@@ -1086,9 +1086,16 @@ dzl_tree_destroy (GtkWidget *widget)
 
   g_assert (DZL_IS_TREE (self));
 
+  gtk_tree_view_set_model (GTK_TREE_VIEW (self), NULL);
+
+  if (priv->store != NULL)
+    {
+      gtk_tree_store_clear (GTK_TREE_STORE (priv->store));
+      g_clear_object (&priv->store);
+    }
+
   g_clear_pointer (&priv->last_drop_path, gtk_tree_path_free);
   g_clear_pointer (&priv->builders, g_ptr_array_unref);
-  g_clear_object (&priv->store);
   g_clear_object (&priv->root);
   g_clear_object (&priv->context_menu);