Attempt to fix problems in high availability guide

Closes-Bug: #1232479

Change-Id: Ief91ccedca2b104df519bccf8e604a7df257dca9
author: diane fleming
EPEL package should only be installed on RHEL and CentOS

Change-Id: I8bf2ead8cca243cfec1fd46a18c6d59614b76580
Merge "Attempt to fix problems in high availability guide"