should handle i18n deprecation warning

## motivation

```
$ be rake spec
[deprecated] I18n.enforce_available_locales will default to true in the future. 
If you really want to skip validation of your locale you can set I18n.enforce_available_locales = false
to avoid this message.
```

## needs review

My guess is that since the web services has no public UI features, we do not need to worry about locales.

- [ ] should `config.i18n.enforce_available_locales` be `true` or `false`?

http://stackoverflow.com/questions/20361428/rails-i18n-validation-deprecation-warning