fixed #198.

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@1323 71c3de6d-444a-0410-be80-ed276b4c234a

core/src/main/resources/hudson/model/Job/buildTimeTrend.jelly

@@ -27,7 +27,7 @@
               </td>
               <j:if test="${isMasterSlaveEnabled}">
                 <td>
-                  <t:node value="${t.builtOn}"/>
+                  <t:node value="${r.builtOn}"/>
                 </td>
               </j:if>
             </tr>