Convert tests to use HRD

Set the HRD consistency policy to 'never' consistent. This breaks a few
tests that need that rely on having changes applies before doing a
query: eg. updating username and logging in. In these cases, the policy
is temporarily set to always consistent.
Fix registration for HRD

RegistrationHandler will now use the model returned by create_user
rather than querying a just written entity, which is likely to fail
test for email change for #239