Updated openstack/openstack
Project: openstack/oslo.concurrency  f7ebc8260d235d474a3dc3135608fec216a4b04c

Clean up API documentation

Use explicit files instead of auto-generating them.

Fail the build on a warning.

Tweak titles and other headings.

Add instructions for using lockutils-wrapper.

Change-Id: Ie92ce14b33180d35d84bbd0998e61b659487481d