Install Guide: Use usual enable/start wording for Sahara
Install Guide: Use usual enable/start wording for Sahara

Use the same wording and flow for starting and enabling a service as
elsewhere.

Change-Id: I7c17383091f94acebdb6c91f21e42a07c28ff9b8

kairoaraujo/openstack-manuals,AlekhyaMallina-Vedams/openstack-manuals,Akasurde/openstack-manuals,gongysh2004/openstack-manual,openstack/openstack-manuals,potsmaster/openstack-manuals,saeki-masaki/openstack-manuals,openstack/openstack-manuals,openstack/openstack-manuals,potsmaster/openstack-manuals,kairoaraujo/openstack-manuals,AlekhyaMallina-Vedams/openstack-manuals,gongysh2004/openstack-manual,openstack/openstack-manuals,AlekhyaMallina-Vedams/openstack-manuals,saeki-masaki/openstack-manuals,Akasurde/openstack-manuals