[entity edition] don't remove values from attribute cache on the repository side
This follows changesets 552de9f0c46d, 1527b012802f, 25da1e5c7c50 and 4ba11607d84a.
closes #2423719 ?
change_attribute_type('CWCache', 'timestamp', 'TZDatetime')
change_attribute_type('CWUser', 'last_login_time', 'TZDatetime')
change_attribute_type('CWSource', 'latest_retrieval', 'TZDatetime')
drop_attribute('CWSource', 'synchronizing')
add_attribute('CWSource', 'in_synchronization')