[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.
sync_schema_props_perms('CWSourceHostConfig', syncperms=False)
sql('INSERT INTO cw_source_relation(eid_from, eid_to) '
'SELECT e.eid,s.cw_eid FROM entities as e, cw_CWSource as s '
'WHERE s.cw_name=e.source AND NOT EXISTS(SELECT 1 FROM cw_source_relation WHERE eid_from=e.eid AND eid_to=s.cw_eid)')
commit()