[dataimport] remove dead code
The only caller of ObjectStore._put is ObjectStore.create_entity, which
RQLObjectStore overrides (and doesn't call up).
# -*- 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 entity's classes"""