system: T5555: Fix time-zone migrator changing valid time-zones to UTC

[sarthurdev]

Change Summary

The migration script system 13-to-14 executes find /usr/share/zoneinfo/posix -type f -or -type l | sed -e s:/usr/share/zoneinfo/posix/:: to find a list of valid timezones. This command only returns the first level of the timezones (continent etc.) resulting in the migrator changing valid timezones to UTC.

This PR changes the command to use timedatectl list-timezones

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/T5555

Component(s) name

system

Proposed changes

How to test

Load config smoketests (ex. basic-vyos and dialup-router-medium-vpn have valid time-zones however are migrated to UTC)

Before:

>>> tz_datas = cmd('find /usr/share/zoneinfo/posix -type f -or -type l | sed -e s:/usr/share/zoneinfo/posix/::')
>>> tz_data = tz_datas.split("\n")
>>> 'Europe/Berlin' in tz_data
False
>>> 'Etc/GMT' in tz_data
False

After:

>>> tz_datas = cmd('timedatectl list-timezones')
>>> tz_data = tz_datas.split("\n")
>>> 'Etc/GMT' in tz_data
True
>>> 'Europe/Berlin' in tz_data
True

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