nfs-utils changed ConditionPathExists from !/etc/krb5.keytab to
/etc/krb5.keytab, so on IPA-joined hosts the service now starts instead
of skipping. Exports use standard auth (no sec=krb5) so the nfs/ Kerberos
principal is never provisioned and the service fails.
enable = false masks the unit so nfs-server's Wants= can't pull it in.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>