[FIXED JENKINS-15499] HistoryWidget/entry.jelly throws NullPointerException

Wrap history iterable to hide class implementation details.
Jelly was getting confused by the history underlying class being implemented
as an extension of Map

changelog.html

@@ -63,6 +63,9 @@ Upcoming changes</a>
 <div id="rc" style="display:none;"><!--=BEGIN=-->
 <h3><a name=v1.491>What's new in 1.491</a> <!--=DATE=--></h3>
 <ul class=image>
+  <li class='major bug'>
+    HistoryWidget/entry.jelly throws NullPointerException
+    (<a href="https://issues.jenkins-ci.org/browse/JENKINS-15499">issue 15499</a>)
   <li class="major bug">
     <code>ArrayIndexOutOfBoundsException</code> or <code>StringIndexOutOfBoundsException</code> launching processes such as Mercurial polling. (Regression in 1.489.)
     (<a href="https://issues.jenkins-ci.org/browse/JENKINS-15733">issue 15733</a>)

core/src/main/java/hudson/widgets/HistoryWidget.java

@@ -26,6 +26,8 @@ package hudson.widgets;
 import hudson.Functions;
 import hudson.model.ModelObject;
 import hudson.model.Run;
+import hudson.util.Iterators;
+
 import org.kohsuke.stapler.Header;
 import org.kohsuke.stapler.HttpResponses;
 import org.kohsuke.stapler.Stapler;
@@ -133,7 +135,7 @@ public class HistoryWidget<O extends ModelObject,T> extends Widget {
                 return updateFirstTransientBuildKey(lst);
             }
         } else
-            return updateFirstTransientBuildKey(baseList);
+            return updateFirstTransientBuildKey(Iterators.wrap(baseList));
     }
 
     public boolean isTrimmed() {