[tests] Port unittest_cwctl to py3k
On python 2, sys.stdout takes bytes-like objects whereas python 3's
takes unicode-like objects and handles the encoding on its own.
for table, column in [
('transactions', 'tx_time'),
('tx_entity_actions', 'tx_uuid'),
('tx_relation_actions', 'tx_uuid')]:
repo.system_source.create_index(session, table, column)
commit()