All of the other Openstack services have a 'public' default endpoint
type. Keystone has 'admin' default endpoint type. Why not make
Keystone compliant and change the default for Keystone v3 from 'admin'
to 'public'. Keystone v2 will remain the same with an 'admin' default.
Closes-Bug: #1457702
Change-Id: I515438477dba72c2a0c4595603000690511b5700