Comment 5 for bug 1553433

I think I found the main problem (among others):
At the end of Runtime.persistent_insert_rule (agnostic.py), the case of having no-changes-made-but-some-disabled is conflated with no-changes-made-and-none-disabled.

Code snippet:
    changes = self._safe_process_policy_update(rule, policy_name)
    if len(changes) > 0:
        ...
        ...

    # change not accepted means it was already there
    raise exception.PolicyRuntimeException(
        name='rule_already_exists')