turn make_relations_query into a true generator (this allows interleaving of actual entities linking and query generation)
restore check botched in previous inadvertent commit
add_relation_type('prefered_form')
rql('SET X prefered_form Y WHERE Y canonical TRUE, X identical_to Y')
checkpoint()
drop_attribute('EmailAddress', 'canonical')
drop_relation_definition('EmailAddress', 'identical_to', 'EmailAddress')
if 'see_also' in schema:
sync_schema_props_perms('see_also', syncprops=False, syncrdefs=False)