code: function updateBrokerCertChain (configDir, certChainFile, certChain, verbosity) {
    var caBundleFileName = util.getConfigFilePath(configDir, certChainFile)
    if (verbosity) {
      console.log('Updating certs in ' + caBundleFileName)
    }
    provisionUtil.saveToFile(caBundleFileName, certChain)
  }
docs: Stores a broker certificate chain into a file.
  @param {String} configDir - Directory in which to store the certificate
  chain. This is only used if certChainFile is not an absolute path to
  an existing certificate chain file.
  @param {String} certChainFile - Name of the file at which to store the
  broker certificate chain.
  @param {String} certChain - Broker certificate chain to store.
  @param {Number} verbosity - Level of verbosity at which to log any error
  or trace messages.
  @private