change pki-core required version for replica promotion
    
    Required PKI changes, namely:
      https://fedorahosted.org/pki/ticket/1414
      https://fedorahosted.org/pki/ticket/1580
    
    Are included in pki-core 10.2.6-5 reps. 10.2.6-10
    
    10.2.7 does not exist yet.
    
    Reviewed-By: Martin Babinsky <mbabinsk@redhat.com>