Enable websocket queries without Origin if zeppelin.server.allowed.origins is *

  public static Boolean isValidOrigin(String sourceHost, ZeppelinConfiguration conf)
      throws UnknownHostException, URISyntaxException {
    if (sourceHost == null || sourceHost.isEmpty()) {
      return false;
    }
    String sourceUriHost = new URI(sourceHost).getHost();
    sourceUriHost = (sourceUriHost == null) ? "" : sourceUriHost.toLowerCase();

    sourceUriHost = sourceUriHost.toLowerCase();
    String currentHost = InetAddress.getLocalHost().getHostName().toLowerCase();

    return conf.getAllowedOrigins().contains("*") ||
        currentHost.equals(sourceUriHost) ||
        "localhost".equals(sourceUriHost) ||
        conf.getAllowedOrigins().contains(sourceHost);
  }