Update configure-nginx.md (#405)

Corrects the command to disable a site (by removing the symlink in `/etc/nginx/sites-enabled/<site-name>`).

Command should be (for the example default site):
`$ sudo rm /etc/nginx/sites-enabled/default`

Author: CrustyBarnacle

how-to/web-services/configure-nginx.md

@@ -80,7 +80,7 @@ $ sudo ln -s /etc/nginx/sites-available/<your-domain> /etc/nginx/sites-enabled/
 To disable a website, you can delete the symlink in `sites-enabled`. For example, once you have your new site(s) configured and no longer need the default site configuration:
 
 ```bash
-$ sudo rm /etc/nginx/sites-available/default
+$ sudo rm /etc/nginx/sites-enabled/default
 ```
 
 ## SSL and HTTPS