Tente isso:
location ~* ^/wordpress/(wp-login\.php|wp-admin) {
fastcgi_cache off;
location ~ \.php$ {
fastcgi_pass unix:/var/run/php5-fpm.sock;
fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
include fastcgi_params;
}
}
location ~ \.php$ {
fastcgi_pass unix:/var/run/php5-fpm.sock;
fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
include fastcgi_params;
}