Patch peer grading tab to work

lms/djangoapps/open_ended_grading/open_ended_notifications.py

 from django.conf import settings
 from staff_grading_service import StaffGradingService
 from open_ended_grading.controller_query_service import ControllerQueryService
+from xmodule import peer_grading_service
 import json
 from student.models import unique_id_for_user
 import open_ended_util
@@ -10,6 +11,8 @@ from courseware.access import has_access
 from util.cache import cache
 import datetime
 from xmodule import peer_grading_service
+from xmodule.x_module import ModuleSystem
+from mitxmako.shortcuts import render_to_string
 
 log=logging.getLogger(__name__)
 
@@ -55,7 +58,8 @@ def staff_grading_notifications(course, user):
     return notification_dict
 
 def peer_grading_notifications(course, user):
-    peer_gs = PeerGradingService(settings.PEER_GRADING_INTERFACE)
+    system = ModuleSystem(None,None,None,render_to_string,None)
+    peer_gs = peer_grading_service.PeerGradingService(settings.PEER_GRADING_INTERFACE, system)
     pending_grading=False
     img_path= ""
     course_id = course.id