Minor update to install doc

Author: ywarnier

documentation/installation_guide.html

@@ -303,7 +303,7 @@ <h2><a name="3._Upgrade_from_a_previous_version_of"></a>3. Upgrade from a
 
 <p></p>
 
-<h3>3.1 Upgrading from Chamilo 1.8.8 </h3>
+<h3>3.1 Upgrading from Chamilo 1.8.8 or 1.8.8.2</h3>
 <ul>
   <li> check that you haven't left any customised stylesheet or image*</li>
   <li> download the Chamilo 1.8.8.4 install package from the <a href="http://www.chamilo.org/download">Chamilo download page</a></li>