openvpn: T3834: verify() is not allowed to change anything on the system (backport #3850)

[mergify]

Change Summary

Commit e3c71af ("remove secrets file if the tunnel is deleted and fix opmode commands") added a code path into verify() which removed files on the system if TOTP was not defined.

This commit moves the code path to the appropriate generate() function.

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/T3834

Related PR(s)

Component(s) name

Proposed changes

How to test

Smoketest result

[email protected]:~$ /usr/libexec/vyos/tests/smoke/cli/test_interfaces_openvpn.py
test_openvpn_client_interfaces (__main__.TestInterfacesOpenVPN.test_openvpn_client_interfaces) ... ok
test_openvpn_client_verify (__main__.TestInterfacesOpenVPN.test_openvpn_client_verify) ... ok
test_openvpn_options (__main__.TestInterfacesOpenVPN.test_openvpn_options) ... ok
test_openvpn_server_subnet_topology (__main__.TestInterfacesOpenVPN.test_openvpn_server_subnet_topology) ... ok
test_openvpn_server_verify (__main__.TestInterfacesOpenVPN.test_openvpn_server_verify) ... ok
test_openvpn_site2site_interfaces_tun (__main__.TestInterfacesOpenVPN.test_openvpn_site2site_interfaces_tun) ... ok
test_openvpn_site2site_verify (__main__.TestInterfacesOpenVPN.test_openvpn_site2site_verify) ... ok

----------------------------------------------------------------------
Ran 7 tests in 67.527s

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 #3850 done by [Mergify](https://mergify.com).

[github-actions]

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No issues in PR Title / Commit Title

[github-actions]

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No issues in unused-imports