add missing param

synapse/handlers/e2e_keys.py

@@ -355,7 +355,7 @@ class E2eKeysHandler(object):
         ret = {"device_keys": res}
 
         # add in the cross-signing keys
-        cross_signing_keys = yield self.query_cross_signing_keys(device_keys_query)
+        cross_signing_keys = yield self.query_cross_signing_keys(device_keys_query, None)
 
         for key, value in iteritems(cross_signing_keys):
             ret[key + "_keys"] = value