httpinstance: wait until the service entry is replicated
    
    Wait until the local HTTP service entry is replicated to the remote master
    before requesting the server certificate.
    
    This prevents a replication conflict between the service entry added
    locally and service entry added remotely when requesting the certificate.
    
    https://pagure.io/freeipa/issue/6867
    
    Reviewed-By: Martin Babinsky <mbabinsk@redhat.com>
    Reviewed-By: Martin Basti <mbasti@redhat.com>