Updates the glossary for Octavia
Updates the glossary for Octavia

1. Fixes a typo for the word "provides".
2. Clarifies that the haproxy driver does not provide high availability.
   (This is why we made the octavia driver)

Change-Id: I70dc3c9ae5bc86d0d6b334a35c140dcfeeb23bd8

openstack/openstack-manuals,openstack/openstack-manuals,openstack/openstack-manuals,openstack/openstack-manuals