Ticket 314 - ChaiOnUpdate for root handling
    
    Bug Description:  If chaining and distribution are configured
    			updates as root are always applied locally
    			This leads to inconsistent data
    
    Fix Description:   Add a configuration option to control the
    			processing of root updates. Valid options are:
    			- local: apply changes to the local database
    			- reject: do not handle root updates
    			- referral: return the referral to the
    					chaining backend
    
    https://fedorahosted.org/389/ticket/314
    
    Reviewed by: ?