Remove circular dependency.
Reviwed in https://codereview.appspot.com/7506043/.
diff --git a/oauth2client/appengine.py b/oauth2client/appengine.py
index a4738f8..570f0f5 100644
--- a/oauth2client/appengine.py
+++ b/oauth2client/appengine.py
@@ -36,7 +36,6 @@
 from google.appengine.ext import webapp
 from google.appengine.ext.webapp.util import login_required
 from google.appengine.ext.webapp.util import run_wsgi_app
-from apiclient import discovery
 from oauth2client import GOOGLE_AUTH_URI
 from oauth2client import GOOGLE_REVOKE_URI
 from oauth2client import GOOGLE_TOKEN_URI
@@ -799,7 +798,7 @@
 
           if decorator._token_response_param and credentials.token_response:
             resp_json = simplejson.dumps(credentials.token_response)
-            redirect_uri = discovery._add_query_parameter(
+            redirect_uri = util._add_query_parameter(
               redirect_uri, decorator._token_response_param, resp_json)
 
           self.redirect(redirect_uri)