Improve install guide openrc content

Improve openrc content in the installation guide as follows:

1) Add new openrc section to keystone chapter
2) Remove clients chapter

This patch implements changes approved for other patches associated
with this blueprint.

Change-Id: I075671cb0b432ce73addb972a0d709f9a4655114
Implements: blueprint installation-guide-improvements
Unified the syntax of the XML root element (arch-design)

The XML root element of Docbook XML files should match the following
format:
<ELEMENT xmlns="http://docbook.org/ns/docbook"
  xmlns:xi="http://www.w3.org/2001/XInclude"
  xmlns:xlink="http://www.w3.org/1999/xlink"
  version="5.0"
  xml:id="THE_XML_ID_OF_THE_ELEMENT">

Change-Id: I6124101642054dddf9a2ff7f1dbb4fa25af51ce9
Add missing new lines at end of file

Change-Id: If3e2910c52f9e92890e0a1efb6dede773023c68a
add the glossterm "Bell-LaPadula modela".

Change-Id: Ic0dd54036c09635dd372c2ea33f20c85130c42dc
Related-Bug: 1342940
Set contentwidth for PDF output on images in Arch Design Guide

Change-Id: Id0e1dc8b027cb178fef17d574a7aaeafc37c0495
Replace the latin abbreviations e.g. and etc

Change-Id: I5a32bfe7258434219ea0e224ecbd96765e482f7e
Adds the Architecture Design Guide to the docs.openstack.org landing page

Change-Id: Ie08d1ccafe7a8658a4c341dca8441ff7a600b568
Arch Design: Update links in prescriptive_examples_compute_focus

Use links that are clickable.

Change-Id: Icb26398e41c6864512b13f0c1024fb26de4f66c1
Configure multiple-storage back ends

Removing hyphen in noun "back end".
(Configure multiple-storage back ends in Section 6.
Block Storage, first sentence)
Closes-Bug: #1346517

Change-Id: Ia53469140972f6e56f77dab55355ace4638e982c
Merge "add the glossterm "Bell-LaPadula modela"."
Merge "Arch Design: Update links in prescriptive_examples_compute_focus"
Merge "Improve install guide openrc content"
Merge "Configure multiple-storage back ends"
Merge "Unified the syntax of the XML root element (arch-design)"
Merge "Add missing new lines at end of file"
Added swift as a trove prerequisite

If you want to use trove for database backups,
you need swift.

The install guide does not state this requirement,
which needs to go on the following page:

http://docs.openstack.org/trunk/install-guide/install/apt/content/trove-install.html

The need to add swift is documented in the
following trove doc scrub etherpad:

https://etherpad.openstack.org/p/trove-doc-items

I added the swift info.

Change-Id: I49102b6c961464f14484797f06949540fe400920
Closes-Bug: #1346438
Merge "Added swift as a trove prerequisite"
Merge "Adds the Architecture Design Guide to the docs.openstack.org landing page"
Merge "Set contentwidth for PDF output on images in Arch Design Guide"