[wwwdocs] Adjust URL for AdaCore Libre Site

[Dave Korn]

Gerald Pfeifer wrote:
> Installed.
> 
> (I would recommend to remove the trailing /libre from the site, Robert.)

  It looks from here like it's optional; there's a redirect:

> $ wget -S 'http://libre.adacore.com/'
> --2009-05-31 02:43:09--  http://libre.adacore.com/
> Resolving libre.adacore.com... 212.99.106.83
> Connecting to libre.adacore.com|212.99.106.83|:80... connected.
> HTTP request sent, awaiting response...
>   HTTP/1.1 302 Found
>   Date: Sun, 31 May 2009 01:31:22 GMT
>   Server: Apache/2.0.54 (FreeBSD) PHP/4.3.11 mod_ssl/2.0.54 OpenSSL/0.9.7c-p1
>   Vary: Host
>   X-Powered-By: PHP/4.3.11
>   X-Pingback: http://libre.adacore.com/xmlrpc.php
>   Location: http://libre.adacore.com/libre/

    cheers,
      DaveK