replica-install: configure key retriever before starting Dogtag
    
    After installing a replica, Dogtag's Lightweight CA key retrieval
    fails until Dogtag is restarted, because the already-running
    instance doesn't pick up the changes to CS.cfg.  Configure the key
    retriever before the instance is started.
    
    Part of: https://fedorahosted.org/freeipa/ticket/4559
    
    Reviewed-By: Jan Cholasta <jcholast@redhat.com>
    Reviewed-By: Martin Babinsky <mbabinsk@redhat.com>