fix(istio): accessing /idp return 404 status code

[iromli]

Describe the bug

When using Istio gateway, accessing /idp (shibboleth) always returns 404 status code. Further inspection shows that /idp is rewritten to /identity.

To Reproduce
Steps to reproduce the behavior:

1. Deploy Gluu with Istio (make sure Shibboleth service is enabled during install prompt)
2. Make request to /idp/shibboleth
3. See 404 status code

Expected behavior

Accessing /idp/shibboleth returns non 404 status code.

[iromli]

@moabu

http:
  - name: {{ .Release.Name }}-istio-oxshibbioleth
    match:
    - uri:
        prefix: /idp
    rewrite:
      uri: /identity

Either rewrite to /idp or remove the rewrite would fix the issue.