private Tuple2<HttpResponse, Integer> checkProtocolVersion(HttpRequest request) {
        return doCheckProtocolVersion(request.getJDiscRequest().headers().get(Headers.VERSION));
    }
Accept feeds from outside the Vespa cluster.

@author Steinar Knutsen
vespaclient-container-plugin/src/main/java/com/yahoo/vespa/http/server/FeedHandler.java