Fixed Regression For PHPCR_ODM Slides URL

A previous commit reverted the PHPCR_ODM slides
url, this patch fixes it.

Author: Anthony Sterling

slides.html

@@ -2384,7 +2384,7 @@ <h1>Quality</h1>
             <h1>Doctrine PHPCR ODM</h1>
             <ul><li>Object - Document mapper to map plain PHP objects to PHPCR data</li>
                 <li>Supports the PHPCR concepts like children and references</li>
-                <li><a href="http://cmf.symfony.com/slides/doctrine-phpcr-odm.html">See the PHPCR-ODM slides</a></li>
+                <li><a href="/slides-odm.html">See the PHPCR-ODM slides</a></li>
             </ul></div>
 
         <div class="slide section">