Disable Sahara in scenario003-standalone
Disable Sahara in scenario003-standalone

Sahara service is deprecated in TripleO and won't be tested anymore to
align with what is delivered downstream.
In the new container image tooling, we don't ship sahara images simply because
we don't have users and won't continue to support it's deployment in the
future.

Change-Id: If1c621b45718475578dca390c45c0e23d1f3d7bc

openstack/tripleo-heat-templates,openstack/tripleo-heat-templates