Replace deprecated "auth_uri" by "www_authenticate_uri"
Replace deprecated "auth_uri" by "www_authenticate_uri"

According to [1], "auth_uri" has been deprecated.
This patch replace it by using "www_authenticate_uri" instead.

[1] https://review.openstack.org/#/c/508522

Change-Id: Id773a00c333c2f81421afef639cbba528d5bc589

openstack/kuryr,openstack/kuryr