fixed discussionBodyTop error

lms/static/coffee/src/discussion/views/discussion_thread_list_view.coffee

@@ -30,7 +30,7 @@ class @DiscussionThreadListView extends Backbone.View
     windowHeight = $(window).height();
 
     discussionBody = $(".discussion-article")
-    discussionsBodyTop = discussionBody.offset().top;
+    discussionsBodyTop = if discussionBody[0] then discussionBody.offset().top;
     discussionsBodyBottom = discussionsBodyTop + discussionBody.outerHeight();
 
     sidebar = $(".sidebar")

lms/templates/discussion/index.html

@@ -28,7 +28,7 @@
         <div class="sidebar"></div>
         <div class="discussion-column">
         	<div class="blank-slate">
-	        	<h1>${course.title} discussion forum</h1>
+	        	<h1>${course.title} discussions</h1>
 
         	</div>
         </div>