[dataimport] Properly escape strings sent to COPY FROM (closes #5278743)
See http://www.postgresql.org/docs/9.1/static/sql-copy.html#AEN64296
for escaping codes.
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()