Instead of having a copy-pasted version in this project, let's just
use the original directly. It is added to the public API of
oslo.utils in the dependency.
Depends-On: https://review.openstack.org/614806
Change-Id: If0dfac2505d097c117ef94c99399b1614f1e1f8f
Consumers of loopingcall may wish to exercise their code in test cases
without incurring actual wall clock sleep time in their test runs.
Heretofore, this required digging into the internals of the loopingcall
module and mocking something private (or something hidden by something
private).
This patch exposes a public oslo_service.fixture.SleepFixture for this
purpose. It can be maintained opaquely as internals change without
affecting its consumers.
See [1] for (one example of) the motivation behind this change.
[1] https://review.openstack.org/#/c/615724/
Change-Id: I0089c7778957456db66599abffaaad3a5332243c