Fix anonymous posts appear are labeled with the logged in user's role

FOR-156

common/static/coffee/spec/discussion/content_spec.coffee

@@ -2,6 +2,22 @@ describe 'All Content', ->
     beforeEach ->
         DiscussionSpecHelper.setUpGlobals()
 
+    describe 'Staff and TA Content', ->
+        beforeEach ->
+            DiscussionUtil.loadRoles({"Moderator": [567], "Administrator": [567], "Community TA": [567]})
+
+        it 'anonymous thread should not include login role label', ->
+            anon_content = new Content
+            anon_content.initialize
+            expect(anon_content.get 'staff_authored').toBe false
+            expect(anon_content.get 'community_ta_authored').toBe false
+
+        it 'general thread should include login role label', ->
+            anon_content = new Content { user_id: '567' }
+            anon_content.initialize
+            expect(anon_content.get 'staff_authored').toBe true
+            expect(anon_content.get 'community_ta_authored').toBe true
+
     describe 'Content', ->
         beforeEach ->
             @content = new Content {

common/static/coffee/src/discussion/content.coffee

@@ -54,8 +54,12 @@ if Backbone?
     initialize: ->
       Content.addContent @id, @
       userId = @get('user_id')
-      @set('staff_authored', DiscussionUtil.isStaff(userId))
-      @set('community_ta_authored', DiscussionUtil.isTA(userId))
+      if userId?
+        @set('staff_authored', DiscussionUtil.isStaff(userId))
+        @set('community_ta_authored', DiscussionUtil.isTA(userId))
+      else
+        @set('staff_authored', false)
+        @set('community_ta_authored', false)
       if Content.getInfo(@id)
         @updateInfo(Content.getInfo(@id))
       @set 'user_url', DiscussionUtil.urlFor('user_profile', userId)