Merge branch '8.x' of git.drupal.org:project/drupal into 8.x

core/CHANGELOG.txt

core/includes/ajax.inc

core/includes/common.inc

core/includes/config.inc

core/includes/errors.inc

core/includes/form.inc

core/includes/install.inc

core/includes/menu.inc

core/includes/schema.inc

core/includes/update.inc

...Drupal/Core/EventSubscriber/MaintenanceModeSubscriber.php

core/misc/machine-name.js

...dules/config/lib/Drupal/config/Tests/ConfigImportTest.php

core/modules/contact/contact.pages.inc

...lib/Drupal/contact/Tests/ContactAuthenticatedUserTest.php

.../contact/lib/Drupal/contact/Tests/ContactSitewideTest.php

core/modules/dblog/config/dblog.settings.yml

core/modules/dblog/dblog.install

core/modules/dblog/dblog.module

core/modules/dblog/lib/Drupal/dblog/Tests/DBLogTest.php