You can clone with
HTTPS or Subversion.
I would line some Drupal site with nginx and php-fpm, but sites use another php-config (socket path, stb.)
It's possible with this config?
Yes, you just have to create another upstream.
And another PHP pool on /etc/php5/fpm/pool.d
Over there, you can customize php configurations and directives.
Okay, If I create another upstream (in upstream_phpcgi_unix.conf), where write in site-wide configuration?
Just replace the upstream by your upstream. What kind of socket are you using? TCP? UNIX?
UNIX socket. I would like, that one site = one PHP socket, PHP-FPM is configured.