[php-fpm] Integration missing fastcgi parameter

[ChannoneArif-nbcuni]

The use of fastcgi is documented here for php-fpm integration

https://docs.datadoghq.com/integrations/php_fpm/#unix-sockets

use_fastcgi = true

This is currently not a supported parameter in integrations/php_fpm.pp

[albertvaka]

Fixed (by yourself, thanks :) in #616