Start frontend http server.

def CreateServer(frontend=None):
  """Start frontend http server."""
  max_port = config.CONFIG.Get("Frontend.port_max",
                               config.CONFIG["Frontend.bind_port"])

  for port in range(config.CONFIG["Frontend.bind_port"], max_port + 1):

    server_address = (config.CONFIG["Frontend.bind_address"], port)
    try:
      httpd = GRRHTTPServer(
          server_address, GRRHTTPServerHandler, frontend=frontend)
      break
    except socket.error as e:
      if e.errno == socket.errno.EADDRINUSE and port < max_port:
        logging.info("Port %s in use, trying %s", port, port + 1)
      else:
        raise

  sa = httpd.socket.getsockname()
  logging.info("Serving HTTP on %s port %d ...", sa[0], sa[1])
  return httpd