[asp.net] Fix for bug #658278. Panels render children only when parent is...

[asp.net] Fix for bug #658278. Panels render children only when parent is present and ChildrenAsTriggers is enabled

Fix from Avior Computing <jmilillo@aviorcomputing.com>, thanks!

mcs/class/System.Web.Extensions/System.Web.UI/UpdatePanel.cs

@@ -321,7 +321,8 @@ namespace System.Web.UI
 					base.RenderChildren (w);
 					w.Flush ();
 					if (sb.Length > 0) {
-						if (ParentPanel != null)
+						UpdatePanel parent = ParentPanel;
+						if (parent != null && parent.ChildrenAsTriggers)
 							writer.Write (sb.ToString ());
 						else
 							ScriptManager.WriteCallbackPanel (responseOutput, this, sb);