[Rdo-list] HA document using application-native tools and keepalived, updated for Kilo

Dear all, Following the RDO Kilo release, I have updated the document describing an architecture for a highly available OpenStack setup using application-native options and keepalived. As part of the update, instructions for Sahara and Trove have been added, and several smaller details have been fixed. You can find the updated document at https://github.com/beekhof/osp-ha-deploy/blob/master/HA-keepalived.md . Of course, the Juno version is still available in a separate branch. Feedback (and PRs) are welcome. I expect to add detailed scenario files using phd (https://github.com/davidvossel/phd) in the future, but that is currently work in progress. Thanks, Javier