Fix Kubelet clusterDNS parameter updating

[Jorge Saffe]

Brief Description
-------------------
If the Kubelet clusterDNS parameter is not defined at bootstrap,
during service-parameter-apply, the parameter is reset to its
IPv4 default value (10.96.0.10).

Severity
---------
major

Steps to Reproduce
------------------
1. Bootstrap a Debian AIO-SX with IPv4 or IPv6.
2. Set a custom DNS service IP.
3. Run service-parameter-apply command.

Expected Behavior
---------------
The Kubelet clusterDNS parameter has not be changed.

Actual Behavior
---------------
The KubeletclusterDNS parameter resets to its default value (10.96.0.10).

Reproducibility
---------------
100%

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/starlingx/stx-puppet/+/879375

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/starlingx/stx-puppet/+/879375
Committed: https://opendev.org/starlingx/stx-puppet/commit/e77bec65911082991dd96b9c52074eaadb5e71dc
Submitter: "Zuul (22348)"
Branch: master

commit e77bec65911082991dd96b9c52074eaadb5e71dc
Author: Jorge Saffe <email address hidden>
Date: Mon Apr 3 14:00:22 2023 -0400

    Fix Kubelet clusterDNS parameter updating

    If the Kubelet clusterDNS parameter is not defined at bootstrap,
    during service-parameter-apply, the parameter is reset to its
    IPv4 default value (10.96.0.10).

    Test Plan:
      PASS: Bootstrap a Debian AIO-SX with IPv4.
      PASS: Run service-parameter-apply command.
      PASS: Verify that clusterDNS parameter has not change.
      PASS: Bootstrap a Debian AIO-SX with IPv6.
      PASS: Run service-parameter-apply command.
      PASS: Verify that clusterDNS parameter has not change.
      PASS: Add, apply and verify invalid parameter test case.
      PASS: Add, apply and verify invalid value test case.
      PASS: Add, apply and verify casting error test case.

    Closes-Bug: 2015119

    Signed-off-by: Jorge Saffe <email address hidden>
    Change-Id: Ic15eb49d0deff05e72620e55b35b4c6b7c17c616