This jira ticket is the following of https://issues.redhat.com/browse/OSPRH-5976

At this point the `heartbeat_in_pthread` option of the rabbitmq driver of oslo.messaging is already depreacted and could be safely removed.

We should be the upstream series after the deprecation.
It is important to leave the time to oslo.messaging users to update their configurations in accordance with the previous scheduled deprecation.