clean up of inconsistency between old and new installations
--
-- Since many years, new installations are created with "Registered
-- Users" (object_id -2) having object_type as "application_group" and
-- the context id of the main subsite (see
-- acs-kernel/sql/postgresql/acs-install.sql).
--
-- However, it seems as if some prior upgrade scripts have not cared
-- sufficiently to update all installation correctly (some have still
-- "group", some have no context_id set). This upgrade script tries to
-- bring everything in sync such that "newer" and "older"
-- installations behave the same.
--
