Allow systemd to run more smoothly

[patcon]

https://rhatdan.wordpress.com/2014/04/30/running-systemd-within-a-docker-container/

When using docker, I seem to get sshd for the node['init_package'] automatic attr, where I would expect systemd. (For example, on CentOS 7)

The above article seems to discuss a solution that would make this attr more as expected. Some cookbooks seem to use that attr to determine the init system, so it seems worth sorting out.