[hooks/syncschema] do not crash when adding a new entity type (closes #2741643)
The previous version assumed META_RTYPES provide relation definitions
for all entity types.
# -*- coding: utf-8 -*-# copyright %(year)s %(author)s, all rights reserved.# contact %(author-web-site)s -- mailto:%(author-email)s#%(long-license)s"""%(distname)s schema"""