Adding variable list to Architecture

Change-Id: Ib9699713371241c7f3eba53b8b356025cfbdd8e0
Closes-Bug: #1289113

doc/common/section_getstart_logical_arch.xml

@@ -5,21 +5,27 @@
   <title>Logical architecture</title>
   <para>To design, deploy, and configure OpenStack, administrators must understand the logical architecture.</para>
   <para>OpenStack modules are one of the following types:</para>
-  <itemizedlist role="compact">
+  <variablelist>
+   <varlistentry><term>Daemon</term>
     <listitem>
-      <para>Daemon. Runs as a background process. On Linux platforms, a daemon is
+      <para>Runs as a background process. On Linux platforms, a daemon is
         usually installed as a service.</para>
     </listitem>
+   </varlistentry>
+   <varlistentry><term>Script</term>
     <listitem>
-      <para>Script. Installs a virtual environment and runs tests. For
+      <para>Installs a virtual environment and runs tests. For
         example, the <code>run_tests.sh</code> script installs a virtual environment and runs unit tests on a service.</para>
     </listitem>
+   </varlistentry>
+   <varlistentry><term>Command-line interface (CLI)</term>
     <listitem>
-      <para>Command-line interface (CLI). Enables users to submit API
+      <para>Enables users to submit API
         calls to OpenStack services through easy-to-use
         commands.</para>
     </listitem>
-  </itemizedlist>
+   </varlistentry>
+  </variablelist>
   <para>The following diagram shows the most common, but not the only,
     architecture for an OpenStack cloud:</para>
   <!-- Source files in this repository in doc/src/docbkx/common/figures/openstack-arch-havana-v1.zip -->
@@ -38,4 +44,4 @@
     through a common Identity Service and individual services interact
     with each other through public APIs, except where privileged
     administrator commands are necessary.</para>
-</section>
+</section>