lint: /var -- warn that content in /var is ignored on updates

[vrothberg]

/var is ignored on updates which is something the linter can warn users about. The issue came up during a meeting with a real-world user example.

[cgwalters]

I believe this is mostly covered by #1101 - but maybe it could use some sterner wording?

Almost certainly the user here didn't have a bootc with that change yet as it was only recently released in 1.1.6.

[vrothberg]

I believe this is mostly covered by #1101 - but maybe it could use some sterner wording?

I agree. The code/check is already there but the current warning is in the context of tempfiles. Maybe the warning can elaborate a bit more on why tempfiles would be needed in addition to mentioning that /var is not subject to updates?

Almost certainly the user here didn't have a bootc with that change yet as it was only recently released in 1.1.6.

Yes, it must have been an older version.