Support multiple conditions together with a JS file per locale.

I consider it a bug, because it is documented, but it doesn't work.
>```
>translations:
>- file: "public/javascripts/i18n/%{locale}.js"
>  only: '*'
>- file: "public/javascripts/frontend/i18n/%{locale}.js"
>  only: ['frontend', 'users']
>```