[DOCS] Applying edits to the OSA install guide: configure
[DOCS] Applying edits to the OSA install guide: configure

Change-Id: I563ecf597d76fc86e85d175c6a348f1b12d33b25
Partial-bug: #1628958

BjoernT/os-ansible-deployment,Logan2211/openstack-ansible,BjoernT/os-ansible-deployment,stackforge/os-ansible-deployment,BjoernT/os-ansible-deployment,cloudnull/os-ansible-deployment,Logan2211/openstack-ansible,stackforge/os-ansible-deployment,yanyao/openstack-ansible,openstack/openstack-ansible,cloudnull/os-ansible-deployment,cfarquhar/openstack-ansible,bunchc/openstack-ansible,robb-romans/openstack-ansible,yanyao/openstack-ansible,cfarquhar/openstack-ansible,BjoernT/openstack-ansible,openstack/openstack-ansible,os-cloud/os-ansible-deployment,robb-romans/openstack-ansible,weezer/openstack-ansible,os-cloud/os-ansible-deployment,bunchc/openstack-ansible,weezer/openstack-ansible,BjoernT/openstack-ansible