KCM: Don't error out if creating a new ID as the first step
    
    We need to handle the case where the nextID operation is ran, but the
    secdb is totally empty, otherwise logins with sssd's krb5_child would
    fail.
    
    Resolves:
    https://pagure.io/SSSD/sssd/issue/3815
    
    Reviewed-by: Michal Židek <mzidek@redhat.com>