Single element ipset array should be in sync with its string equivalent

[2fa]

Summary

Currently if you have a single value ipset parameter it will always be trying to correct itself on every puppet run.

Additional info

I tried to create proper acceptance test for this case but it requires installed ipset package with created ipsets for testing so i decided not to do it.

Checklist

• [x] 🟢 Spec tests.
• [x] 🟢 Acceptance tests.
• [x] Manually verified. (For example puppet apply)