test: workaround gentoo systemd-resolved issue

[rsutton1]

PR progress checklist (to be filled in by reviewers)

• Changes to documentation are appropriate (or tick if not required)
• Changes to tests are appropriate (or tick if not required)
• Reviews completed

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What type of PR is this?

Primary type

• [build] Changes related to the build system
• [chore] Changes to the build process or auxiliary tools and libraries such as documentation generation
• [ci] Changes to the continuous integration configuration
• [feat] A new feature
• [fix] A bug fix
• [perf] A code change that improves performance
• [refactor] A code change that neither fixes a bug nor adds a feature
• [revert] A change used to revert a previous commit
• [style] Changes that do not affect the meaning of the code (white-space, formatting, missing semi-colons, etc.)

Secondary type

• [docs] Documentation changes
• [test] Adding missing or correcting existing tests

Does this PR introduce a BREAKING CHANGE?

No.

Related issues and/or pull requests

Describe the changes you're proposing

When attempting to use kitchen to test the Gentoo image with systemd, the DNS doesn't resolve. I found this issue systemd/systemd#9771 which appears to be the issue I'm seeing; if the DNS server doesn't support DNSSEC, then systemd-resolved fails DNS resolution.

After making this change, which turns off DNSSEC, it allows kitchen tests for Gentoo to pass again.

Pillar / config required to test the proposed changes

git clone [email protected]:rsutton1/nvim-formula.git
cd nvim-formula
git checkout 57e546ffae6f2b3993db07c73c8e5d8383981100~1 # the commit immediately before the fix
bundle exec kitchen test default-gentoo-stage3-systemd-3004-1-py3 # this should fail with DNS resolution issue
git checkout 57e546ffae6f2b3993db07c73c8e5d8383981100 # check out the fix
bundle exec kitchen test default-gentoo-stage3-systemd-3004-1-py3 # this should work

Debug log showing how the proposed changes work

Here's the fix commit. If you click the red X, you'll see the Gentoo test passed. (The overall job failed due to unrelated issues): rsutton1/nvim-formula@57e546f

Documentation checklist

• Updated the README (e.g. Available states).
• Updated pillar.example.

Testing checklist

• Included in Kitchen (i.e. under state_top).
• Covered by new/existing tests (e.g. InSpec, Serverspec, etc.).
• Updated the relevant test pillar.

Additional context