Proper config dictionary generation for controller query

lms/djangoapps/open_ended_grading/open_ended_util.py

 from django.conf import settings
+import logging
+
+log=logging.getLogger(__name__)
 
 def get_controller_url():
-    peer_grading_url = settings.PEER_GRADING_INTERFACE
+    peer_grading_url = settings.PEER_GRADING_INTERFACE['url']
     split_url = peer_grading_url.split("/")
     controller_url = "http://" + split_url[2] + "/grading_controller"
-    return controller_url
+    controller_settings=settings.PEER_GRADING_INTERFACE
+    controller_settings['url'] = controller_url
+    return controller_settings