version：istio: 0.6.0 + Ubuntu 16.04.2 LTS

Hi,

I run bookinfo example in kube by the guide. I did some changes of the example to test the authority of routerule rewrite. But I found it did not work. Can someone give me a hint? Below are what I did:

1. I changed the detail request url from 'http://details:9080/details/0' to 'http://ratings:9080/v1/details/0' in productpage service,and restart the service.
2. add a rewrite rule(detail-rewrite) of detail to rewrite "/v1/details" to '/details'
3. add a redirect rule(rate2detail) of ratings to redirect 'ratings' to 'details'
4. refresh the demo page. the demo is ok, it can get the detail info. (redirect success)
5. then I replace rate2detail to rate2detail rewrite.
6. refresh the demo page and now the the detail request fails. (rewrite not work)

Below are the rules:

detail-rewrite

apiVersion: config.istio.io/v1alpha2
kind: RouteRule
metadata:
  name: detail-rewrite
spec:
  ## Used by services inside the Kubernetes cluster
  destination:
    name: details
  match:
    request:
      headers:
        uri:
          prefix: /v1/details
  rewrite:
    uri: /details

rate2detail

apiVersion: config.istio.io/v1alpha2
kind: RouteRule
metadata:
  name: rate2detail
spec:
  ## Used by services inside the Kubernetes cluster
  destination:
    name: ratings
  redirect:
    authority: details:9080

rate2detail rewrite

apiVersion: config.istio.io/v1alpha2
kind: RouteRule
metadata:
  name: rate2detail
spec:
  ## Used by services inside the Kubernetes cluster
  destination:
    name: ratings
  rewrite:
    authority: details:9080