Feed error messages through a cors wrapper so that people on other domains can see what's happening.

endpoints/api/repotoken.py

@@ -1,10 +1,9 @@
 import logging
 
 from flask import request
-from flask.ext.restful import abort
 
 from endpoints.api import (resource, nickname, require_repo_admin, RepositoryParamResource,
-                           log_action, validate_json_request)
+                           log_action, validate_json_request, NotFound)
 from data import model
 
 
@@ -97,7 +96,7 @@ class RepositoryToken(RepositoryParamResource):
     try:
       perm = model.get_repo_delegate_token(namespace, repository, code)
     except model.InvalidTokenException:
-      abort(404)
+      raise NotFound()
 
     return token_view(perm)