Cleanup _build_federated_info
Cleanup _build_federated_info

There was a lot of duplicated code that made this function hard to
follow.

Change-Id: Ia067f75a18e29958eb87654232baf5a5437ca073

ilay09/keystone,himanshu-setia/keystone,mahak/keystone,rajalokan/keystone,rajalokan/keystone,ajayaa/keystone,openstack/keystone,mahak/keystone,cernops/keystone,klmitch/keystone,cernops/keystone,rajalokan/keystone,openstack/keystone,klmitch/keystone,ilay09/keystone,ilay09/keystone,maestro-hybrid-cloud/keystone,ajayaa/keystone,maestro-hybrid-cloud/keystone,himanshu-setia/keystone,mahak/keystone,dims/keystone,openstack/keystone,dims/keystone