[migration] set a cnxset before process_script()
Not pretty, but I don't have a better idea right now and this at least
ensures migration scripts get run in the expected environment and can
access sql stuff as before.
from datetime import datetime
for rtype in ('cw_support', 'cw_dont_cross', 'cw_may_cross'):
drop_relation_type(rtype)
add_entity_type('CWSourceSchemaConfig')
if not 'url' in schema['CWSource'].subjrels:
add_attribute('CWSource', 'url')
add_attribute('CWSource', 'parser')
add_attribute('CWSource', 'latest_retrieval')