[gnome-control-center] window, shell-model: Silence warnings

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit 16f06665dd1670b55b350b85db75770c762d98b9
Author: Georges Basile Stavracas Neto <georges stavracas gmail com>
Date:   Wed May 2 22:34:23 2018 -0300

    window, shell-model: Silence warnings
    
    A fallback from the previous commit.

 shell/cc-shell-model.c | 6 +++---
 shell/cc-window.c      | 2 +-
 2 files changed, 4 insertions(+), 4 deletions(-)
---
diff --git a/shell/cc-shell-model.c b/shell/cc-shell-model.c
index 2a69d6a12..220063075 100644
--- a/shell/cc-shell-model.c
+++ b/shell/cc-shell-model.c
@@ -336,16 +336,16 @@ cc_shell_model_has_panel (CcShellModel *model,
 
   g_assert (id);
 
-  valid = gtk_tree_model_get_iter_first (model, &iter);
+  valid = gtk_tree_model_get_iter_first (GTK_TREE_MODEL (model), &iter);
   while (valid)
     {
       g_autofree gchar *panel_id = NULL;
 
-      gtk_tree_model_get (model, &iter, COL_ID, &panel_id, -1);
+      gtk_tree_model_get (GTK_TREE_MODEL (model), &iter, COL_ID, &panel_id, -1);
       if (g_str_equal (id, panel_id))
         return TRUE;
 
-      valid = gtk_tree_model_iter_next (model, &iter);
+      valid = gtk_tree_model_iter_next (GTK_TREE_MODEL (model), &iter);
     }
 
   return FALSE;
diff --git a/shell/cc-window.c b/shell/cc-window.c
index c05712475..f8dbc0ffb 100644
--- a/shell/cc-window.c
+++ b/shell/cc-window.c
@@ -756,7 +756,7 @@ cc_window_init (CcWindow *self)
   /* After everything is loaded, select the last used panel, if any,
    * or the first visible panel */
   id = g_settings_get_string (self->settings, "last-panel");
-  if (id != NULL && cc_shell_model_has_panel (self->store, id))
+  if (id != NULL && cc_shell_model_has_panel (CC_SHELL_MODEL (self->store), id))
     cc_panel_list_set_active_panel (CC_PANEL_LIST (self->panel_list), id);
   else
     cc_panel_list_activate (CC_PANEL_LIST (self->panel_list));