Adds swift ring replica count adjustability to Cloud Admin Guide

Added info on adjustability of ring replica counts to Object Storage section of Cloud Admin Guide

Change-Id: I5c6580ef553ab01cd5e77bb68c7db00d8f6e3014
backport: havana
Closes-Bug: #1095505
author: nermina miller
Merge "Adds swift ring replica count adjustability to Cloud Admin Guide"