Revert "REFACTOR: support booting discourse with DISCOURSE_NO_CONSTANTS"

This reverts commit c0b277d273.

test/javascripts/controllers/flag-test.js.es6

@@ -1,5 +1,4 @@
 import createStore from 'helpers/create-store';
-import AdminUser from 'admin/models/admin-user';
 
 var buildPost = function(args) {
   return Discourse.Post.create(_.merge({
@@ -10,7 +9,7 @@ var buildPost = function(args) {
 };
 
 var buildAdminUser = function(args) {
-  return AdminUser.create(_.merge({
+  return Discourse.AdminUser.create(_.merge({
     id: 11,
     username: 'urist'
   }, args || {}));