Nanobsd included copies of ssh_config and sshd_config. The former is identical to the one provided by the base system, and the latter is identical except for PermitRootLogin, which is updated by nanobsd's cust_allow_ssh_root anyhow. Remove nanobsd's copies and use the existing ones.
Reported by: Jose Luis Duran <jlduran@gmail.com> Sponsored by: The FreeBSD Foundation