Comment 3 for bug 1743603

I think we should remove the warning log from keystonemiddleware.
The service token is from nova to keystone, and the keystone service does not contain this parameter. And keystone service just authenticates the token wether it is user token or service token. If the keystonemiddleware judge the token is allowed expired and then the keystone service authenticate the token with 'allow_expired' parameter.

So I think it is just the log waning confuses.
See https://review.openstack.org/#/c/548736/