[FIX]Fixed the issue of pad button not rendered when deletes a pad from the attachment area.

bzr revid: msh@tinyerp.com-20120529074017-6woyh00mz8fl18v0

addons/web/static/src/js/view_form.js

@@ -802,6 +802,7 @@ openerp.web.form.SidebarAttachments = openerp.web.OldWidget.extend({
                 ids: [parseInt($e.attr('data-id'))]
             }, function(r) {
                 $e.parent().remove();
+                self.do_update()
                 self.do_notify("Delete an attachment", "The attachment '" + name + "' has been deleted");
             });
         }