net-dns has a bug (https://github.com/bluemonk/net-dns/issues/46) that
causes this error to hit whenever the nameserver lookup via TCP times
out.  To fix this problem in the short term, use our fork of this
repository and pull in the fix
(https://gitlab.com/gitlab-org/gitlab-net-dns/merge_requests/2).

Closes https://gitlab.com/gitlab-org/gitlab/issues/11634