Resolves issue #4038 where the X-Forwarded-Port header would be set to the value of the https listening port if all of the following settings were satisfied:
- The ingress controller was started with a non-default HTTPS port set with the `--https-port` argument
- An ingress is created having:
- the `nginx.ingress.kubernetes.io/auth-url` annotation set
- TLS enabled
This commit solves this issue by moving the setting of the `pass_server_port` variable from the server, one level down to the location context.
