[install-guide] update draft note for Liberty
[install-guide] update draft note for Liberty

Change-Id: I7da03723c81eda4d7e9bc5759e720b8db2f51b1e

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