updated changelog for release

changelog.html

@@ -55,6 +55,11 @@ Upcoming changes</a>
 
 <!-- Record your changes in the trunk here. -->
 <div id="trunk" style="display:none"><!--=TRUNK-BEGIN=-->
+<ul class=image>
+  <li class=>
+</ul>
+</div><!--=TRUNK-END=-->
+<h3><a name=v2.18>What's new in 2.18</a> (2016/08/15)</h3>
 <ul class=image>
   <li class="rfe">
     Better diagnostics and robustness against old <code>ChangeLogAnnotator</code> API usage in plugins.
@@ -96,7 +101,6 @@ Upcoming changes</a>
      <a href="https://github.com/jenkinsci/jenkins/pull/2498">PR #2498</a>
      )
 </ul>
-</div><!--=TRUNK-END=-->
 <h3><a name=v2.17>What's new in 2.17</a> (2016/08/05)</h3>
 <ul class=image>
   <li class="major bug">