Make the WP.com concat script work out of the box

[BronsonQuick]

One of our devs was asking how to get this to work. @rmccue replied with this:

Chassis' site config loads `include /etc/nginx/sites-available/<%= @fqdn %>.d/*;
So if you make a `/etc/nginx/sites-available/vagrant.local.d/wpcom-concat.conf`, you can chuck that in there

Let's see if we can get the extension to set this up automagically.

[stuartshields]

@BronsonQuick I'll work on this over the next few days and see what I can come up with.