[BUG] No log generated with non-working config

[JohnVillalovos]

I have the following non-working config.

<?php

/** !!!!!!!!!!!! DEPRECATED !!!!!!!!!!!!!!!!!!
 * This file is deprecated and will be removed in a future release.
 * Please use config.dist.php instead and set $conf['settings']['app.debug'] = 'true';.
 * !!!!!!!!!!!! DEPRECATED !!!!!!!!!!!!!!!!!!
 */
$conf['settings']['inactivity.timeout'] = '527040';
$conf['settings']['api']['enabled'] = 'true';
$conf['settings']['logging']['folder'] = '/var/log/librebooking';
$conf['settings']['use.local.js.libs'] = 'true';               // false recommended, delivers jQuery from Google CDN, uses less bandwidth
$conf['settings']['default.timezone'] = 'America/Los_Angeles';
$conf['settings']['install.password'] = 'lb_install_passwd';
$conf['settings']['script.url'] = 'http://lb.example.com/Web';                           // public URL to the Web directory of this instance. this is the URL that appears when you are logging in. leave http: or https: off to auto-detect
ini_set('display_errors', 1);

No log is generated in /var/log/librebooking/ which makes it difficult to debug the config.