FIX: proper error message when account created is hit with no session

app/controllers/users_controller.rb

@@ -436,7 +436,7 @@ class UsersController < ApplicationController
   end
 
   def account_created
-    @message = session['user_created_message']
+    @message = session['user_created_message'] || I18n.t('activation.missing_session')
     expires_now
     render layout: 'no_ember'
   end

config/locales/server.en.yml

@@ -475,7 +475,7 @@ en:
     continue_button: "Continue to %{site_name}"
     welcome_to: "Welcome to %{site_name}!"
     approval_required: "A moderator must manually approve your new account before you can access this forum. You'll get an email when your account is approved!"
-
+    missing_session: "We can not detect if your account was created, please ensure you have cookies enabled."
   post_action_types:
     off_topic:
       title: 'Off-Topic'