message: readme: fix example
diff: @@ -166,7 +166,7 @@ In the following example all errors triggered by admins will be ignored:
  ```js
  airbrake.addFilter(function(notice) {
  - if (notice.sessions.admin) {
  + if (notice.params.admin) {
  // Ignore errors from admin sessions.
  return null;
  }
  