smoketest: T5705: use locally connected remote syslog servers (backport #3889)

[mergify]

Change Summary

As there has been no route to the configured syslog servers, smoketests produced:

rsyslogd: omfwd: socket 8: error 101 sending via udp: Network is unreachable

Rather use some fake syslog servers from 127.0.0.0/8 which are directly connected and we do not need to look up a route, which will suppress the above error message.

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/T5705

Related PR(s)

Component(s) name

smoketest

Smoketest result

cpo@LR2.wue3:~$ /usr/libexec/vyos/tests/smoke/cli/test_system_syslog.py
test_syslog_basic (__main__.TestRSYSLOGService.test_syslog_basic) ... ok

----------------------------------------------------------------------
Ran 1 test in 3.027s

OK

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

---

This is an automatic backport of pull request #3889 done by [Mergify](https://mergify.com).

[github-actions]

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warning: Unused import os in smoketest/scripts/cli/test_interfaces_l2tpv3.py:17.

[github-actions]

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