add mysql_optional as dsn parameter

[Thomblin]

This pull requests adds mysql_ssl_option as an dsn paramter to pt-online-schema-change.

Why?

Upgrading debian from bullseye to bookworm or trixie changes the behaviour of perl DBI. As a consequence perl DBI is not able to use ssl anymore when enforced (pt-online-schema-change raises the exception "SSL connection error: Enforcing SSL encryption is not supported").

See: Debian Bug Report 1032074

I found no fix for this (using official sources). The only workaround to make it work is calling pt-online-schema-change with both mysql_ssl=1 and mysl_ssl_optional=1

Please advice how and if tests or documentation need to be adjusted.

• The contributed code is licensed under GPL v2.0
• Individual Contributor License Agreement is signed
• util/update-modules has been ran
• Documentation updated
• Test suite update

[it-percona-cla]

All committers have signed the CLA.

[svetasmirnova]

Immediate workaround is to install DBD::mysql, depending on upstream or Percona libmysql, available in Percona repositories.

I will check proposed solution, so Percona Toolkit can run with default DBD::mysql, linked to libmariadb3 too. Currently I can only say that you modified auto-generated code that will be rewritten once we create packages or simply update modules. Check CONTRIBUTING.md for how to update modules and create tests for your contributions.

[Thomblin]

@svetasmirnova I added the option to lib and tests