only first rule works in nirvana.yaml

[moshuipan]

Is this a BUG REPORT or FEATURE REQUEST?:
/kind bug

What happened:
edit nirvana.yaml

......
versions:
- name: v1
  rules:
  - prefix: /apis/v1
  - prefix: /healthz
......

only first rule /apis/v1 works
What you expected to happen:
api.json contains healthz
How to reproduce it (as minimally and precisely as possible):

Anything else we need to know?:
generator.go
path = rule.Replace(path)
the path will be set to empty if rule do not match .