Updated openstack/openstack
Project: openstack/oslo.i18n  75ea61a87b07137114c8a6df857016ed4c4a668f

Remove mention of Message objects from public docs

The Message class is not part of the public API of the library, so don't
refer to it in documentation that appears for the public API.

Change-Id: Ie28ce6f8f2c2de351c8a233b7de9dc31abaa9e04