Links to the newui preserve state

appengine/swarming/templates/restricted_botslist.html

 {% extends "swarming/base.html" %}
 
 
 {% block headers %}
 <style>
   h1 {
     margin-top: 10px;
     margin-bottom: 10px;
   }
 
@@ skipping 51 matching lines @@
 </script>
 {% endblock %}
 
 
 {% block body %}
 {% import 'swarming/bot_view.html' as bot_view %}
 
 <h1>Known bots</h1>
 <a href="/">Back to root</a>
 <br/>
-<a href="/newui/botlist">Try out the new bot list</a>
+<a href="{{try_link}}">Try out the new bot list UI</a>
 <p/>
 <form id="filter_and_order" name="filter_and_order" method="GET">
 <table>
   <tr>
     <td>
       <table class=property_table>
         <tbody>
           <tr>
             <td>Current bot version</td>
             <td>{{current_version[:8]}}</td>
@@ skipping 94 matching lines @@
     {% endfor %}
   </tbody>
 </table>
 
 {% if cursor %}
 <p/>
 <a href="/restricted/bots?limit={{limit}}&sort_by={{sort_by}}&cursor={{cursor|urlencode}}&dimensions={{dimensions|urlencode}}">Next page</a>
 {% endif %}
 
 {% endblock %}