op mode: T3355: remove the mention of legacy non-image installations

[dmbaturin]

We still have a conditional for detecting "legacy non-image installations" in show version. Such installations were never supported by VyOS — that check was only relevant for very old systems upgraded from Vyatta Core instances that were created with install system instead of install image. Even Vyatta Core itself dropped support for that post 6.1 (or so), so such systems certainly don't exist in the wild now.

Change Summary

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Code style update (formatting, renaming)
• Refactoring (no functional changes)
• Migration from an old Vyatta component to vyos-1x, please link to related PR inside obsoleted component
• Other (please describe): legacy code removal

Related Task(s)

Related PR(s)

Component(s) name

Proposed changes

How to test

Smoketest result

Checklist:

• I have read the CONTRIBUTING document
• I have linked this PR to one or more Phabricator Task(s)
• I have run the components SMOKETESTS if applicable
• My commit headlines contain a valid Task id
• My change requires a change to the documentation
• I have updated the documentation accordingly

[c-po]

@Mergifyio backport sagitta

[mergify]

backport sagitta

✅ Backports have been created

• #3461 op mode: T3355: remove the mention of legacy non-image installations (backport #3457) has been created for branch sagitta