fix for underscore template issue for xmodules

lms/templates/discussion/_underscore_templates.html

@@ -175,6 +175,7 @@
   <div class="discussion-article blank-slate">
   <section class="home-header">
   <span class="label">DISCUSSION HOME:</span>
+  % if course and course.display_name_with_default:
   <h1 class="home-title">${course.display_name_with_default}</h1>
   </section>
   
@@ -221,6 +222,7 @@
   </tr>
   </table>
   % endif
+  % endif
 
   </div>    
 </script>