Cherry-pick from the release-0.4 branch

* Fix issues in admin guide

   comments mentioned in https://review.openstack.org/#/c/65926/
   document style (XML style, formatting issues)

   Closes-Bug: 1268537

* Resolve documentation issues

   Fix comments that was not fixed in original
   Closes-bug: #1268537

* Update documentation for a release-0.4.1 release

   Closes-bug: #1268537

Change-Id: I5bf3f01500dc4023e5477e5173d4f6a9922bd034