IE compatibility

$(e).next() may return undefined.
If 2nd argument of insertBefore is undefined,
IE9 complains "SCRIPT87: Invalid argument".
To insert newChild at the end, 2nd argument should be null.
http://www.w3.org/TR/2000/REC-DOM-Level-2-Core-20001113/core.html#ID-952280727

changelog.html

@@ -63,6 +63,9 @@ Upcoming changes</a>
 <div id="rc" style="display:none;"><!--=BEGIN=-->
 <h3><a name=v1.454>What's new in 1.454</a> <!--=DATE=--></h3>
 <ul class=image>
+  <li class=bug>
+    Fixed a regression in 1.453 with IE9
+    (<a href="https://github.com/jenkinsci/jenkins/pull/397">pull 397</a>)
   <li class=bug>
     Fixed NPE in Groovy script execution via CLI (<a href="https://issues.jenkins-ci.org/browse/JENKINS-12302">issue 12302</a>)
   <li class=bug>

war/src/main/webapp/scripts/hudson-behavior.js

@@ -743,7 +743,7 @@ var jenkinsRules = {
     "INPUT.auto-complete": function(e) {// form field with auto-completion support 
         // insert the auto-completion container
         var div = document.createElement("DIV");
-        e.parentNode.insertBefore(div,$(e).next());
+        e.parentNode.insertBefore(div,$(e).next()||null);
         e.style.position = "relative"; // or else by default it's absolutely positioned, making "width:100%" break
 
         var ds = new YAHOO.util.XHRDataSource(e.getAttribute("autoCompleteUrl"));