doc: WARNING: term not in glossary: availability zone

[Takashi Natsume]

The 'tox -e docs' fails because of the following warnings.

2020-04-12 03:10:46.170060 | ubuntu-bionic | /home/zuul/src/opendev.org/openstack/nova/doc/source/admin/aggregates.rst:27: WARNING: term not in glossary: availability zone

2020-04-12 03:10:46.170144 | ubuntu-bionic | /home/zuul/src/opendev.org/openstack/nova/doc/source/admin/configuration/schedulers.rst:27: WARNING: term not in glossary: availability zone

2020-04-12 03:10:46.170177 | ubuntu-bionic | /home/zuul/src/opendev.org/openstack/nova/doc/source/reference/glossary.rst:35: WARNING: term not in glossary: availability zone

https://zuul.opendev.org/t/openstack/build/e8f374e5f54f4adfa0c2e5ca8fdb58fa/log/job-output.txt

It is due to the following change in the sphinx.

https://github.com/sphinx-doc/sphinx/pull/7440

This change has been merged into sphinx 3.0.1.

https://github.com/sphinx-doc/sphinx/blob/v3.0.1/CHANGES#L7

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/719318

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/719318
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=2e299a6e72015e8708ee0329fb03bb8c9f67ae69
Submitter: Zuul
Branch: master

commit 2e299a6e72015e8708ee0329fb03bb8c9f67ae69
Author: Takashi Natsume <email address hidden>
Date: Sun Apr 12 13:01:24 2020 +0900

    doc: Fix term mismatch warnings in glossary

    The term role has became case sensitive since sphinx 3.0.1.
    It causes the following warnings and makes a check job fail.

      WARNING: term not in glossary: availability zone

    This patch fixes the issue.

    Change-Id: I1f993b503ef769da0950afa206d6ac4a54f903b4
    Closes-Bug: #1872260