Better follow conventions in HA Guide

Follow our conventions for title capitalization and usage of
project/service names.

Follow conventions on using active voice, no -ing for titles.

Co-Authored-By: Diane Fleming <diane.fleming@rackspace.com>

Change-Id: I05e368f8dda436454d2daca1a6775105032a39fc
Partial-Bug: #1217503
Merge "Better follow conventions in HA Guide"