Fix flaky e2e test

[lubronzhan]

…ne VIP
Fix #771

Assume VIP is routable even if API server returns 500, since that means VIP is routable, it just might be because etcd is glitching.

Another way to fix is to increase the timeout, but I think better not to increase that since 30s is already a long time
considering the default config

- name: vip_leaseduration
      value: "5"
    - name: vip_renewdeadline
      value: "3"
    - name: vip_retryperiod
      value: "1"

[thebsdbox]

This is fine for me, Obviously 200 would be better as it proves Kubernetes is up and running.. but we're testing the VIP not the API server.