Returning 401 if user is not authenticated

Change-Id: Idbf1887ad64fd698568a0a7e069cfb0512df8a55
diff --git a/xos/xos/exceptions.py b/xos/xos/exceptions.py
index 9ab2605..b3631e4 100644
--- a/xos/xos/exceptions.py
+++ b/xos/xos/exceptions.py
@@ -15,6 +15,7 @@
                             "fields": fields})
 
 class XOSNotAuthenticated(RestFrameworkPermissionDenied):
+    status_code=401
     def __init__(self, why="you must be authenticated to use this api", fields={}):
         APIException.__init__(self, {"error": "XOSNotAuthenticated",
                             "specific_error": why,