'80' is the port used by default but it's possible configuring it.

Hi Andy,

I made the gitlabhq port configurable (by default it would be '80' and '443' if SSL).
Also, the disabling of the default nginx site have been modified to use the nginx cookbook method:
```
nginx_site 'default' do
  enable false
end
```

Most probably this should be made optional if there is a  port conflict, and otherwise rely on the nginx cookbook itself to disable the default it that's what someone really wants (in my setup I'm already disabling the default site, for instance).