config.inc.php: remove constant TB_OBJECT_MODELS_AUTHORITATIVE.

This was used in module coreupdater only, which was changed to
test for the existence of class CoreModels instead. As this
constant was never in a release, it can get removed without
retrocompatibility period.

This reverts commit 202e5af.

Also forwarded module coreupdater to the point working without
this constant.

config/config.inc.php

@@ -39,16 +39,6 @@
 
 $start_time = microtime(true);
 
-/**
- * This constants exists to tell CoreUpdate to consider object models definitions
- * as an ultimate source of truth. Database tables will be migrated to match
- * these definitions if there are any differences.
- *
- * Because this constant didn't exist in older version of thirtybess, downgrading will
- * not trigger any database changes
- */
-define('TB_OBJECT_MODELS_AUTHORITATIVE', true);
-
 /* SSL configuration */
 define('_PS_SSL_PORT_', 443);