lib/util/newrelic.js
function NewRelic(license_key, options, log) {
  this.url = "https://api.newrelic.com";
  this._options = options;
  this.license_key = license_key;

  if (!this._options.hasOwnProperty('user')) {
    this._options['user'] = 'dreadnot';
  }

  this.log = log || logmagic.local('sensu');
}
function NewRelic(license_key, options, log) {
  this.url = "https://api.newrelic.com";
  this._options = options;
  this.license_key = license_key;

  if (!this._options.hasOwnProperty('user')) {
    this._options['user'] = 'dreadnot';
  }

  this.log = log || logmagic.local('sensu');
}
Hopefully newrelic retained backwards compatibility since the code here was most likely written for v1 of their api 
NewRelic Client.
@constructor
@param {Object} options The options.