nginx vhost view doesn't detect whether php is running on a port or a socket.

src/Amp/views/nginx-vhost.php assumes we are running php on port 9000 rather than on a socket. Is there any way that we can test for this and create an appropriate config? Maybe look for 

```
listen = /var/run/php5-fpm.sock
```

in /etc/php5/fpm/pool.dfpm/pool.d/www.conf or similar?

If not trivial, we should potentially add this as a gotcha or similar in the documentation.
