Adding link to swift3 repo to docs

fixes bug 1076222

Swift3 was moved to an external repo. This patch adds the additional
instructions to download and install it.

Change-Id: I41374e0520474ea83973b7a54be3124a10dd5587

doc/src/docbkx/openstack-object-storage-admin/objectstorageadmin.xml

@@ -1235,10 +1235,17 @@ memcache time for the key).
             <listitem><para>HEAD Object</para></listitem>
             <listitem><para>PUT Object</para></listitem>
             <listitem><para>PUT Object (Copy)</para></listitem></itemizedlist>
-
+            <para> To use this middleware, first download the latest version from its repository.
+            to your proxy server(s).
+            <screen>
+            <prompt>$</prompt> <userinput>git clone https://github.com/fujita/swift3.git</userinput>
+            </screen>
+            Then, install it using standard python mechanisms, such as:
+            <screen><prompt>$</prompt><userinput> sudo python setup.py install</userinput></screen></para>
             <para>To add this middleware to your configuration, add the swift3 middleware in front
             of the auth middleware, and before any other middleware that look at swift requests
             (like rate limiting). </para>
+
     <para>Ensure that your proxy-server.conf file contains swift3 in the pipeline and the
             [filter:swift3] section, as shown below:</para>
         <programlisting>