The Ironic templates and roles assume Keystone is enabled and they don't
make use of the `enable_keystone var. This patch changes the behavior so
that `noauth` is used as auth method for Ironic if keystone is not
enabled, the Ironic endpoint is not registered if keystone is not
enabled and the keystone section is not created in the config file.
Change-Id: I813de42d10ac264eec81076cb107b58af09ff686
bbe9d418ba