Fix Sahara puppet manifests for Fuel 6.0 (Juno)

* change name for sahara service;
* migrate from custom auth_token middleware config options to
the common config options;
* remove sahara-dashboard installing, because now sahara-dashboard
is integrated into Horizon Openstack Dashboard;
* add icehouse backward compatibility for dashboard
and keystone settings

Closes-bug: #1364934
Change-Id: I29d931c1ee0f9a22bcdddc38b59680285ab68f36
blueprint fuel-deploy-juno
Merge "Fix Sahara puppet manifests for Fuel 6.0 (Juno)"