Bug # 1189296 - Add links to official Red Hat cloud images.

Add links to the "KVM Guest Image" and boot.iso image provided by Red
Hat for use in cloud environments.

Cherry-picked from https://review.openstack.org/#/c/32382/

Change-Id: Ia68aa26a276c0c529fcd420bda666714cfe24578

doc/src/docbkx/openstack-image/ch_obtaining_images.xml

@@ -41,6 +41,24 @@
                     <literal>ubuntu</literal>.</para>
             </note></para>
         </section>
+        <section xml:id="redhat-images">
+            <title>Official Red Hat Enterprise Linux images</title>
+            <para>
+              Red Hat maintains an official Red Hat Enterprise Linux 6 cloud
+              image. A valid Red Hat Enterprise Linux 6 subscription is required
+              to download the <link
+                  xlink:href="https://rhn.redhat.com/rhn/software/channel/downloads/Download.do?cid=16952"
+                >KVM Guest Image</link>.
+            </para>
+            <para>
+              A <link
+              xlink:href="https://rhn.redhat.com/rhn/software/channel/downloads/Download.do?cid=10486"
+              >boot.iso</link> image is also available. This is the same as the
+              <literal>boot.iso</literal> file provided on the Red Hat
+              Enterprise Linux installation DVD. It is a minimal image suitable
+              for kickstarting operating system installation over a network.
+            </para>
+        </section>
     <section xml:id="suse-sles-images">
         <title>Official openSUSE and SLES images</title>
         <para>SUSE does not provide openSUSE or SUSE Linux Enterprise