RegisterForm is 2.0 only

svn path=/trunk/mcs/; revision=49585

mcs/class/System.Web/System.Web.UI.HtmlControls/HtmlForm.cs

@@ -205,7 +205,9 @@ namespace System.Web.UI.HtmlControls
 		{
 			Page.RegisterViewStateHandler ();
 
+#if NET_2_0
 			Page.RegisterForm (this);
+#endif
 
 			base.OnInit (e);
 		}