wrapper = function(handlers, elem) {
            while (handlers.length) {
                this.deleteHandler(handlers.pop());
            }
            this._sasl_auth1_cb.bind(this)(elem);
            return false;
        }
PrivateFunction: _sasl_success_cb
 _Private_ handler for succesful SASL authentication.

 Parameters:
   (XMLElement) elem - The matching stanza.

 Returns:
   false to remove the handler.