The country code specified in the Accept-Language HTTP header is ignored when computing the current locale

Follow this steps to reproduce:

1. Create a new wiki page with this content:

   {{velocity}}
   $services.localization.currentLocale
   {{/velocity}}
   

2. Configure your browser to ask for Brazilian Portuguese language
3. Logout
4. Clear the existing cookies
5. Access the wiki page created in the first step

You get 'pt' although we would expect 'pt_BR'.

You can check the HTTP headers of the request. I got:

pt-BR,en-US;q=0.7,en;q=0.3

so 'pt-BR' is included as first option.

The problem comes from XWiki.getAcceptedLanguages() which keeps only the language code (ignoring the country code).