update cert template-remove additional signatories (#169)

comprehensive/lms/templates/certificates/_accomplishment-rendering.html

@@ -221,14 +221,6 @@ course_mode_class = course_mode if course_mode else ''
 	     Microsoft
 	   </p>
 	 </div>
-	 <div class="ar-signature">
-	   <img src="/static/comprehensive/images/director-sign.png" height="50" width="150" alt="Director Signature"/>
-	   <p>
-	     <strong>Björn Rettig</strong><br/>
-	     Senior Director of School of Applied Technology<br/>
-	     Microsoft
-	   </p>
-	</div>
       </div>
     </div>
     <div class="ar-body-ribbon">