retry on HTTP 50X Error when calling Chef REST API

1) retrying_http_errors is called by retriable_rest_request in rest.rb. retriable_rest_request is marked as deprecated, and I don't find any code call retriable_rest_request.
2) retrying_http_errors is called by send_http_request in http.rb. Since the client.request in yield block for retrying_http_errors never raises Net::* exceptions., the "resue Net::HTTPFatalError" is useless.