Merge pull request #537 from MITx/feature/cale/xqueue_callback_url_proto

Pull the http or https from the forwarded proto for the xqueue callback ...

lms/djangoapps/courseware/module_render.py

@@ -199,7 +199,10 @@ def _get_module(user, request, location, student_module_cache, course_id, positi
                        )
 
     # Fully qualified callback URL for external queueing system
-    xqueue_callback_url  = request.build_absolute_uri('/')[:-1] # Trailing slash provided by reverse
+    xqueue_callback_url = '{proto}://{host}'.format(
+        host=request.get_host(),
+        proto=request.META.get('HTTP_X_FORWARDED_PROTO', 'https' if request.is_secure() else 'http')
+    )
     xqueue_callback_url += reverse('xqueue_callback',
                                   kwargs=dict(course_id=course_id,
                                               userid=str(user.id),