I had to boot from an .iso and mount up the filesystem to reset it. Also disabled selinux on reboot. If you find it out, please post, I'm curious myself.
Based on https://access.redhat.com/site/solutions/641193 the root account is disabled but sudo is granted to the uid 'cloud-user'. Basically, it is configured to use cloud-init and be provisioned ssh keys.
If a root password is required, the KB recommends using 'guestfish --rw -a <image>', mounting the filesystem, and running vi against /etc/shadow.