OAuth *was* being defaulted to enabled: true deliberately.  The key and secret are being generated during installation .  The primary reason is to make nodes (both parent and child) installations easier.  If there is a good reason for making this change, you also need to remove the %post scriptlet that generates the key and secret.  Having these values commented out breaks that script.  Also, the nodes installation guide needs to be updated to additionally instruct the user to edit server.conf: set enabled: true and set the key and secret.