Fix 29654 (Unable to Delete messages or Cancel News Messages from menu) r=mscott, a=phil

mailnews/base/resources/content/widgetglue.js

@@ -263,6 +263,7 @@ function CommandUpdate_Mail()
 			messagePane.removeAttribute('draw-focus-border');
 	}*/
 		
+	goUpdateCommand('cmd_delete');
 	goUpdateCommand('button_delete');
 }