Nginx: Fix the typo - the control file should be /etc/nginx/basic_nginx.conf

To enable basic config:

$ touch /etc/nginx/basic_nginx.conf
$ su -s /bin/bash - aegir -c "drush @hostmaster hosting-task @server_master verify --force -d"

To enable extended config:

$ rm -f /etc/nginx/basic_nginx.conf
$ su -s /bin/bash - aegir -c "drush @hostmaster hosting-task @server_master verify --force -d"

Note that only basic->extended switch is safe, while extended->basic switch will break sites config, until all vhosts will be re-verified to use correct include and match updated main, bare bones config. A simple workaround would be to replace the included config file with:

$ cd /var/aegir/config/includes/
$ cp -af nginx_simple_include.conf nginx_advanced_include.conf
$ service nginx reload