In the current implementation, in the `sub` claim value
`secret:{zuul tenant}/{canonical project name}/{secret name}`
the `{secret name}` is the Ansbile var name defined in
`job.secrets.name` while it should be the `secret.name`.
This change fixes this issue by switch to use `secret.name`.
Change-Id: I9cccc5f14bb0ff17f389c14e89c35fb979ea5c49