Http api shards

It might be easier to write a helper:

```go
func MustGetHTTP(url string) (status int, body string) {
  resp, err := http.Get(s.URL + `/db/foo/shards`)
  if err != nil {
    panic("http get error: " + err.Error())
  }
  status = resp.StatusCode
  body, _ = ioutil.ReadAll(resp.Body)
  resp.Body.Close()
  return
}
```