mysqlctl: Remove usage of MYSQL_FLAVOR

[dbussink]

After the changes in #13123, I realized that there's no cases left where we actually use or depend on MYSQL_FLAVOR.

This means we can actually remove usages of MYSQL_FLAVOR. It doesn't yet remove it from the artifacts we build, because we shouldn't clean that up until v18 then because users might mix versions during the upgrade and we don't want to have old code that still depends on this fail then.

Related Issue(s)

Follow up to #13123

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[vitess-bot]

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[dbussink]

Found some remaining references in the docs which I'm cleaning up in vitessio/website#1479.

[mattlord]

I like it! The MYSQL_FLAVOR related behavior always felt very unintuitive to me for a variety of reasons (e.g. mysql56 is really about MySQL GTID replication and that's it AFAIK).

Thanks!

[mattlord]

@dbussink the only thing that I think we might want to do is add a note to the v17 release notes summary that this ENV var is no longer used. IMO we should do that. What do others think?

[dbussink]

@dbussink the only thing that I think we might want to do is add a note to the v17 release notes summary that this ENV var is no longer used. IMO we should do that. What do others think?

Happy to do so if others also agree. @deepthi Do you have an opinion on this?

[deepthi]

@dbussink the only thing that I think we might want to do is add a note to the v17 release notes summary that this ENV var is no longer used. IMO we should do that. What do others think?

Happy to do so if others also agree. @deepthi Do you have an opinion on this?

Yes, let's do that. Also, the examples need to be updated to match. I checked the examples and they already don't set this ENV var, so that part is good.

[deepthi]

💯