Issue 4068: Make the auto logout more obvious

https://code.google.com/p/otwarchive/issues/detail?id=4068

If someone could write some text about cookies going missing ? I can update this with some proper text.
This should actually be: 

```
<%= render 'layouts/header' %>
<div id="inner" class="wrapper">
  <div id="main" class="system region" role="main">
  <h2 class="heading"><%= ts('Forced Logout') %></h2>

    <div class="userstuff">
      <p><%= ts("You have been automatically logged out to protect your privacy.  Please make sure that your browser is set to accept cookies from archiveofourown.org and delete any existing Archive cookies.  If you continue to have problems logging in, please")%> <%= link_to ts('contact support.'), new_feedback_report_path %></p>
    </div>
  </div>
</div>
```

I'm also getting a weird display issue with a lot of extra whitespace above the header: 
![extra_space](https://cloud.githubusercontent.com/assets/907055/4100435/ec4a7a10-3096-11e4-971d-21cf8cc2674e.png)

When I inspect the source, I can see it's from a text node that shouldn't be there, but I can't figure out where the text node is coming from:
![empty_text_node](https://cloud.githubusercontent.com/assets/907055/4100778/9f3ac040-30b4-11e4-8d45-543012420649.png)

The position makes it look like it's unrelated to this file, but this is the only page it's happening on.