change "four service components" to "three service components"
change "four service components" to "three service components"

Change-Id: I64b2adf8d63e95caac504408082aedefe8c29622
Closes-Bug: #1575948

openstack/openstack-manuals,AlekhyaMallina-Vedams/openstack-manuals,openstack/openstack-manuals,AlekhyaMallina-Vedams/openstack-manuals,openstack/openstack-manuals,AlekhyaMallina-Vedams/openstack-manuals,openstack/openstack-manuals