Restructure Object Storage chapter of Cloud Admin Guide

Restores Troubleshoot Object Storage
Removes Monitoring section, which was based on a blog

backport: havana
Closes-Bug: #1251515
author: nermina miller

Change-Id: I580b077a0124d7cd54dced6c0d340e05d5d5f983
(cherry picked from commit 2163ad9a00359ad128be807c0f65f5e831d9ba66)
Fixes the metadata agent configration

backport: havana

Change-Id: I262f954d61a9af2b74baf566cfe6258cc2044417
Closes-bug:#1262084
(cherry picked from commit 33efabf7087a7a8fd43bfd0e7c0af0d2c32efa30)
Merge "Fixes the metadata agent configration" into stable/havana
Merge "Restructure Object Storage chapter of Cloud Admin Guide" into stable/havana