Don't manage CA file/directory permissions

Puppet6 no longer reads to or writes from the CA related files, but we weren't able to move the settings to puppetserver in time for 6. Several of the settings still define an owner, group, mode which means puppet could in theory attempt to manage the permissions on those files. This doesn't happen in practice, because puppet never calls Puppet.settings.use(:ca), but an custom application could. To be sure that never happens, we should remove owner, group, mode from the settings in the :ca section.

/cc maggie. justin