Log Message:
Update to latest release, 3.0.16. From ChangeLog:

- ``kombu[librabbitmq]`` now depends on librabbitmq 1.5.1.
- Redis: Fixes ``TypeError`` problem in ``unregister`` (Issue #342).
- Tests: Some unit tests accidentally required the `redis-py` library.
- librabbitmq: Would crash when using an older version of :mod:`librabbitmq`,
  now emits warning instead.