message: bug: Store XHR breadcrumb only when readyState === 4
diff: @@ -1118,7 +1118,7 @@ Raven.prototype = {
  var xhr = this;
  function onreadystatechangeHandler() {
  - if (xhr.__raven_xhr && (xhr.readyState === 1 || xhr.readyState === 4)) {
  + if (xhr.__raven_xhr && xhr.readyState === 4) {
  try {
  // touching statusCode in some platforms throws
  // an exception
  @@ -1126,6 +1126,7 @@ Raven.prototype = {
  } catch (e) {
  /* do nothing */
  }
  +
  self.captureBreadcrumb({
  type: 'http',
  category: 'xhr',
  