Do not fail if there are multiple nsDS5ReplicaId values in cn=replication,cn=etc
    
    On systems installed before #3394 was fixed and nsDS5ReplicaId became
    single-valued, there are two replica ID values stored in cn=replication:
    the default (3) and the actual value we want.
    Instead of failing when multiple values are found, use the largest one.
    
    https://fedorahosted.org/freeipa/ticket/4375
    
    Reviewed-By: Martin Kosek <mkosek@redhat.com>