explicitly do AAAA lookups even if IPv6 is unavailable

[kjetilho]

Resolv will only return IPv6 records if there is a local IPv6 address, and this is problematic since the agent may be in a completely different situation than the master - where this code runs.

Resolv will by default only return AAAA records if there are any IPv6 addresses on the host in question. It does this logic itself, it is not based on getaddrinfo or gai.conf.

Summary

This changes host_to_ip so it uses an explicit DNS lookup for the relevant type of DNS record depending on address family.

Additional Context

Since this code is run on the master, it may be singlestack (typical for Kubernetes deployment), while the agent consuming the catalog is dualstack. This mismatch causes the agent to get the wrong set of firewall rules.

It should be noted that Resolv will never use anything other than DNS to resolve addresses, so addresses in /etc/hosts do not work neither before nor after this patch.

Checklist

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