In manila/api/openstack/rest_api_version_history.rst,
underscores were used instead of hyphens to underline version '2.14'.
Fix to remove visual incongruity.
In doc/source/devref/scheduler.rst, not all drivers were added or
updated. Fix to include all drivers.
Partially-implements bp improve-manila-developer-docs
Change-Id: I513a4b51ab5f3d8c0cdb5aa013c93ecd07a85a20
724d8dfa0a