image-tools: T5883: preserve file owner in /config on add system update

[jestabro]

Change Summary

The /config dir has the set-group-id bit set for group ownership when copying the directory on 'add system image'; user ownership is ignored as in general root is correct. However, for Kea dhcp leases stored in /config/dhcp, this will cause a problem --- preserver user on copy when updating.

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):

Related Task(s)

• https://vyos.dev/T5883

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

[jestabro]

@Mergifyio backport sagitta

[mergify]

backport sagitta

✅ Backports have been created

• #2733 image-tools: T5883: preserve file owner in /config on add system update (backport #2731) has been created for branch sagitta