Nil request body with retry

middlewares/retry.go

@@ -35,6 +35,9 @@ func (retry *Retry) ServeHTTP(rw http.ResponseWriter, r *http.Request) {
 	// cf https://github.com/containous/traefik/issues/1008
 	if retry.attempts > 1 {
 		body := r.Body
+		if body == nil {
+			body = http.NoBody
+		}
 		defer body.Close()
 		r.Body = ioutil.NopCloser(body)
 	}