Issue #2249723: \Drupal::config() does not work in .drush.inc file, remove \Drupal::config()
Issue #2249723 by andrei.dincu: Few changes in xmlsitemap_help() hook
Issue #2249723 by andrei.dincu: Replace lock_acquire and lock_release from xmlsitemap.module
Issue #2249723 by andrei.dincu: Replace LANGUAGE_NONE with LanguageInterface::LANGUAGE_NOT_SPECIFIED in xmlsitemap.generate.inc, replace variable_get() with \Drupal::config()->get in xmlsitemap.module and xmlsitemap.xmlsitemap.inc