Add Sahara to the client listing

Sahara is missing in the table "OpenStack services and clients"
in the CLI reference (included from common) at the moment.

According to https://github.com/openstack/governance/blob/master/reference/programs.yaml
Sahara is an integrated project since Juno. Clients of integrated projects should be
listed.

Change-Id: I110be4b1840107bb6285dcb2738a5c76f97d29f1
Merge "Add Sahara to the client listing"