title: FacesMessage is not displayed when being set in an action method with a redirect outcome
body: <p>Why the code from the first block works and the other one doesn't? It's all about displaying JSF messages</p>
  
  <pre><code>@PostConstruct
  public void init() {
      try {
          throw new RuntimeException();
      } catch (RuntimeException e) {
          i18nExceptionHandler.handleException(e);
      }
  }
  </code></pre>
  
  <p>The code above works well - it displays the message.</p>
  
  <pre><code>public String login() {
      try {
         //login actions
      } catch (AuthenticationException e) {
        //this doesn't work
          i18nExceptionHandler.handleException(e);
      }
      return "/pages/loggedin?faces-redirect=true";
  }
  </code></pre>
  
  <p>This code doesn't work - it doesn't display any message and I'm given following error: </p>
  
  <pre><code>WARNING: There are some unhandled FacesMessages, this means not every FacesMessage had a chance to be rendered.
  </code></pre>
  
  <p>Why it works like that? Shall I use validator or something else on the login method (and the rest as well)?</p>