[install] documented enabled_apis to be changed
[install] documented enabled_apis to be changed

Change-Id: Ia783f942950d5679f27d3a5d0672ab11b5208209
Closes-Bug: #1592768

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