Ticket 601 - multi master replication allows schema violation
    
    Bug Description:  If a required attribute has two values, it is possible
    			to delete them concurrently on different masters.
    			The delete of a single value is valid, but after
    			the deletes are replicated all values are gone.
    
    Fix Description:   In the state of update resoultion it is too late to reject
    			any of the deletes (and it would require schema check
    			in the update resolution process), they have been acked
    			to the client.
    			What could an dshould be done is to detect this situation
    			log an error and flag the entry with a replConflict.
    			To do this schema checking for mods has to be done for replicated
    			operations and the slapi_enty_schema_check function needs
    			to be extended.
    
    https://fedorahosted.org/389/ticket/601
    
    Reviewed by: ?