Nova Cells in charm-deployment-guide reference percona

[Andrea Ieri]

This bug tracker is for errors with the documentation, use the following as a template and remove or add fields as you see fit. Convert [ ] into [x] to check boxes:

- [x] This doc is inaccurate in this way: Focal deployments use innodb
- [ ] This is a doc addition request.
- [ ] I have a fix to the document that I can paste below including example: input and output.

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-----------------------------------
Release: 0.0.1.dev416 on 2021-10-27 16:31:55
SHA: 7a5914976f70b86bd41d1a772f01f851f70b8191
Source: https://opendev.org/openstack/charm-deployment-guide/src/deploy-guide/source/nova-cells.rst
URL: https://docs.openstack.org/project-deploy-guide/charm-deployment-guide/latest/nova-cells.html

The current nova cells v2 docs state that:

> Each cell requires the following charms:
>
> * nova-cell-controller
> * rabbitmq-server
> * percona-cluster
> * nova-compute

Focal clouds require the mysql-innodb cluster instead[0], so the documentation should be updated accordingly (or clearly state why percona is necessary if that were to be the case).

[0] https://docs.openstack.org/project-deploy-guide/charm-deployment-guide/latest/percona-series-upgrade-to-focal.html

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/openstack/charm-deployment-guide/+/827081

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/charm-deployment-guide/+/827081
Committed: https://opendev.org/openstack/charm-deployment-guide/commit/296535ad2f04fd749120cbd69d4f72592bb16597
Submitter: "Zuul (22348)"
Branch: master

commit 296535ad2f04fd749120cbd69d4f72592bb16597
Author: Marcin Wilk <email address hidden>
Date: Mon Jan 31 13:00:25 2022 +0000

    Replace Percona XtraDB with MySQL InnoDB Cluster

    Starting from Ubuntu 20.04 LTS (Focal) percona-cluster charm is no
    longer supported. Deployments have been using mysql-innodb-cluster
    charm instead. This update addresses corresponding documentation
    changes.

    Also aligned all `code` and `note` blocks according to the guidelines.

    Closes-Bug: #1949240
    Change-Id: Ibfee80a051f349154f4753689f28280f510a7162