The last allowed/mapping rule can be removed in SPs
    
    If you created rule(s) in an SP for either allowed attributes or
    attribute mapping there was no way to remove the last rule meaning
    it could never go back to use the global defaults.
    
    https://fedorahosted.org/ipsilon/ticket/25
    
    Signed-off-by: Rob Crittenden <rcritten@redhat.com>
    Reviewed-by: Simo Sorce <simo@redhat.com>