bug fix.

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@5219 71c3de6d-444a-0410-be80-ed276b4c234a

core/src/main/resources/hudson/widgets/HistoryWidget/entry.jelly

@@ -21,7 +21,7 @@
     </td>
   </tr>
   <j:if test="${build.building}">
-    <j:set target="it" property="nextBuildNumberToFetch" value="${it.number}"/>
+    <j:set target="${it}" property="nextBuildNumberToFetch" value="${build.number}"/>
     <tr class="transitive"><td></td><td style="padding:0">
       <table class="middle-align">
         <tr><td>