Cleanup fernet validate_v3_token
Cleanup fernet validate_v3_token

Move trust_ref definition down to where it's actually used to make
the code clearer.

Change-Id: I27f16908d87e055c42acda2e25a81595f8e83998

ilay09/keystone,cernops/keystone,ilay09/keystone,ilay09/keystone,himanshu-setia/keystone,himanshu-setia/keystone,klmitch/keystone,mahak/keystone,rajalokan/keystone,openstack/keystone,cernops/keystone,mahak/keystone,dims/keystone,openstack/keystone,rajalokan/keystone,dims/keystone,klmitch/keystone,openstack/keystone,rajalokan/keystone,mahak/keystone