chef-zero binds to ::1 even if you disable IPv6

[balasankarc]

In regard to https://gitlab.com/gitlab-org/omnibus-gitlab/issues/576 .

Even if ipv6 is disabled in system, chef-zero binds to ::1, and makes omnibus-ctl take too much time. Fixed it with running chef-client with --chef-zero-host 127.0.0.1 option.

Is this a valid fix? What are the thoughts on a PR to omnibus-ctl's use of chef-client?

[smith]

Is there a (cross-platform, in Ruby or otherwise) way to check if ipv6 is enabled on a system and conditionally set this option? Seems like using ipv6 by default is the right thing to do in the long term, but falling back to v4 if necessary would be good too.