Refactor global var setup for forum Jasmine tests

Originally reviewed in #4072

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

 describe 'All Content', ->
     beforeEach ->
-        # TODO: figure out a better way of handling this
-        # It is set up in main.coffee DiscussionApp.start
-        window.$$course_id = 'edX/999/test'
-        window.user = new DiscussionUser {id: '567'}
+        DiscussionSpecHelper.setUpGlobals()
 
     describe 'Content', ->
         beforeEach ->

common/static/coffee/spec/discussion/discussion_spec_helper.coffee

+class @DiscussionSpecHelper
+    # This is sad. We should avoid dependence on global vars.
+    @setUpGlobals = ->
+        DiscussionUtil.loadRoles({"Moderator": [], "Administrator": [], "Community TA": []})
+        window.$$course_id = "edX/999/test"
+        window.user = new DiscussionUser({id: "567", upvoted_ids: []})

common/static/coffee/spec/discussion/view/discussion_content_view_spec.coffee

 describe "DiscussionContentView", ->
     beforeEach ->
-
+        DiscussionSpecHelper.setUpGlobals()
         setFixtures(
             """
             <div class="discussion-post">
@@ -36,7 +36,6 @@ describe "DiscussionContentView", ->
         @thread = new Thread(@threadData)
         @view = new DiscussionContentView({ model: @thread })
         @view.setElement($('.discussion-post'))
-        window.user = new DiscussionUser({id: '567', upvoted_ids: []})
 
     it 'defines the tag', ->
         expect($('#jasmine-fixtures')).toExist

common/static/coffee/spec/discussion/view/discussion_thread_list_view_spec.coffee

 describe "DiscussionThreadListView", ->
 
     beforeEach ->
-
+        DiscussionSpecHelper.setUpGlobals()
         setFixtures """
         <script type="text/template" id="thread-list-item-template">
           <a href="<%- id %>" data-id="<%- id %>">
@@ -75,8 +75,6 @@ describe "DiscussionThreadListView", ->
           {id: "2", title: "Thread2", body: "dummy body", votes: {up_count: '42'}, unread_comments_count:0, comments_count:2, created_at: '2013-04-03T20:07:39Z',},
           {id: "3", title: "Thread3", body: "dummy body", votes: {up_count: '12'}, unread_comments_count:0, comments_count:3, created_at: '2013-04-03T20:06:39Z',},
         ]
-        window.$$course_id = "TestOrg/TestCourse/TestRun"
-        window.user = new DiscussionUser({id: "567", upvoted_ids: []})
 
         spyOn($, "ajax")
 

common/static/coffee/spec/discussion/view/discussion_thread_show_view_spec.coffee

 describe "DiscussionThreadShowView", ->
     beforeEach ->
+        DiscussionSpecHelper.setUpGlobals()
         setFixtures(
             """
             <div class="discussion-post">
@@ -14,8 +15,6 @@ describe "DiscussionThreadShowView", ->
             """
         )
 
-        window.$$course_id = "TestOrg/TestCourse/TestRun"
-        window.user = new DiscussionUser({id: "567", upvoted_ids: []})
         @threadData = {
             id: "dummy",
             user_id: user.id,

common/static/coffee/spec/discussion/view/discussion_user_profile_view_spec.coffee

 describe "DiscussionUserProfileView", ->
     beforeEach ->
+        DiscussionSpecHelper.setUpGlobals()
         setFixtures(
             """
             <script type="text/template" id="_user_profile">
@@ -46,7 +47,6 @@ describe "DiscussionUserProfileView", ->
             <div class="user-profile-fixture"/>
             """
         )
-        window.$$course_id = "dummy_course_id"
         spyOn(DiscussionThreadProfileView.prototype, "render")
 
     makeView = (threads, page, numPages) ->

common/static/coffee/spec/discussion/view/response_comment_show_view_spec.coffee

 describe 'ResponseCommentShowView', ->
     beforeEach ->
+        DiscussionSpecHelper.setUpGlobals()
         # set up the container for the response to go in
         setFixtures """
         <ol class="responses"></ol>

common/static/coffee/spec/discussion/view/response_comment_view_spec.coffee

 describe 'ResponseCommentView', ->
     beforeEach ->
-        window.$$course_id = 'edX/999/test'
-        window.user = new DiscussionUser {id: '567'}
-        DiscussionUtil.loadRoles []
+        DiscussionSpecHelper.setUpGlobals()
         @comment = new Comment {
                 id: '01234567',
                 user_id: user.id,

common/static/coffee/spec/discussion/view/thread_response_show_view_spec.coffee

 describe "ThreadResponseShowView", ->
     beforeEach ->
+        DiscussionSpecHelper.setUpGlobals()
         setFixtures(
             """
             <div class="discussion-post">
@@ -22,7 +23,6 @@ describe "ThreadResponseShowView", ->
         @comment = new Comment(@commentData)
         @view = new ThreadResponseShowView({ model: @comment })
         @view.setElement($(".discussion-post"))
-        window.user = new DiscussionUser({id: "567", upvoted_ids: []})
 
     it "renders the vote correctly", ->
         DiscussionViewSpecHelper.checkRenderVote(@view, @comment)