Don't renderAttrs unnecessarily

It is unneeded here, and causes bad behavior.

common/static/coffee/src/discussion/views/discussion_thread_view.coffee

@@ -278,7 +278,6 @@ if Backbone?
       comment = new Comment(body: body, created_at: (new Date()).toISOString(), username: window.user.get("username"), votes: { up_count: 0 }, abuse_flaggers:[], endorsed: false, user_id: window.user.get("id"))
       comment.set('thread', @model.get('thread'))
       @renderResponseToList(comment, ".js-response-list")
-      @renderAttrs()
       @model.addComment()
       @renderAddResponseButton()