fixed issue 1010, error reporting on list:string

gluon/contrib/login_methods/oauth20_account.py

@@ -107,7 +107,7 @@ server for requests.  It can be used for the optional"scope" parameters for Face
             path_info = next
         else:
             path_info = r.env.path_info
-        uri = '%s://%s%s' %(url_scheme, http_host, path_info)
+        uri = '%s://%s%s' % (url_scheme, http_host, path_info)
         if r.get_vars and not next:
             uri += '?' + urlencode(r.get_vars)
         return uri