[web test] repair test broken by 0872ac2a1db0
after the above cset, during test instance's url is set before the creation of
core entities (ie created at database initialization), hence they have now a
valid cwuri.
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')