Actually show correct template description

Fixes #742

include/staff/tpl.inc.php

@@ -71,7 +71,7 @@ $tpl=$msgtemplates[$selected];
    <thead>
      <tr>
         <th colspan="2">
-            <h4><?php echo Format::htmlchars($nfo['desc']); ?></h4>
+            <h4><?php echo Format::htmlchars($tpl['desc']); ?></h4>
             <em>Subject and body required.  <a class="tip" href="ticket_variables.txt">Supported Variables</a>.</em>
         </th>
      </tr>