[gtk+] Avoid a warning if GtkCellView has no model

[Matthias Clasen <matthiasc src gnome org>]

commit cfe909848d399de90be3fce57c30e1f25610a9c6
Author: Matthias Clasen <mclasen redhat com>
Date:   Thu Jan 20 22:35:09 2011 -0500

    Avoid a warning if GtkCellView has no model

 gtk/gtkcellview.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/gtk/gtkcellview.c b/gtk/gtkcellview.c
index e47f861..bec061d 100644
--- a/gtk/gtkcellview.c
+++ b/gtk/gtkcellview.c
@@ -577,6 +577,9 @@ gtk_cell_view_request_model (GtkCellView        *cellview,
   GtkTreeIter         iter;
   gboolean            valid;
 
+  if (!priv->model)
+    return;
+
   valid = gtk_tree_model_iter_children (priv->model, &iter, parent);
   while (valid)
     {