Updated openstack/openstack
Project: openstack/oslo.messaging  3578338f3a7b29c052e2b8e357940a25a22b54ed

Fix structure of unit tests in oslo.messaging (part 2)

Even in case of libraries and when they are not big like nova.
It is better to use next rules:
1) structure of tests directory is the same as a root of project
Tests directory will be well organized, and it will be simple to find
where to write tests
2) names for end modules should be test_<name_of_testing_module>.py

Change-Id: I069121c5f32bbe51c6795e51c23ff3630fcd43e2