Multi-domain and "Could not load the settings file at" error

When using external libraries like CKEditor, CiviCRM tries to locate civicrm.settings.php by guessing its location using civicrm_conf_init in the file civicrm.config.php

Most of the time it works fine but it doesn't work in this specific case :

• Drupal 7
• several domains used for the same site (using domain access module for example)

The reason is that the domains definition are in the file drupal/sites/sites.php which is not taken into account by civicrm_conf_init.

The error we get is then : "Could not load the settings file at: .../all/modules/civicrm/../../../default/civicrm.settings.php" which is the fallback behavior when the directory corresponding to the domain is not found.

The patch consist in reading the file sites/sites.php if it exist and find the corresponding directory.