Only specify the ipatokenuniqueid default in the add operation
    
    Specifying the default in the LDAP Object causes the parameter to be specified
    for non-add operations. This is especially problematic when performing the
    modify operation as it causes the primary key to change for every
    modification.
    
    https://fedorahosted.org/freeipa/ticket/4227
    
    Reviewed-By: Petr Viktorin <pviktori@redhat.com>