inherit locale and drupal sub-domain language detection and civicrm in a sub-folder

Bug specific to:

• multi-lingual installations with at least 2 languages
• drupal, using the "domain" to detect the locale (not path prefix)
• drupal/civicrm is installed in a sub-folder of the web server, ex: http://fr.example.org/mysite/
• it's a full moon

In those cases, the CRM_Utils_System_Drupal::languageNegotiationURL() doesn't return the correct URL.

I will do a PR and more testing, but for now, the patch is:

        //domain
        if ($urlType == LOCALE_LANGUAGE_NEGOTIATION_URL_DOMAIN) {
          if (isset($language->domain) && $language->domain) {
            if ($addLanguagePart) {
              $url = (CRM_Utils_System::isSSL() ? 'https' : 'http') . '://' . $language->domain . base_path(); // <- this
            }