[FIXED JENKINS-17724] /about was not showing licenses.

A recent Stapler update caused the Jelly facet to ignore *.xml.
So need to use raw j:include (as plugins were doing), not st:include (as core did).

changelog.html

@@ -57,6 +57,9 @@ Upcoming changes</a>
 <ul class=image>
   <li class=rfe>
     Can use <code>-Dhudson.udp=-1</code> to disable UDP broadcast without showing an ugly exception.
+  <li class=bug>
+    Third-party license display for core was broken since 1.506.
+    (<a href="https://issues.jenkins-ci.org/browse/JENKINS-17724">issue 17724</a>)
   <li class=rfe>
     <code>/about</code> now links to license information for plugins as well.
   <li class=rfe>

core/src/main/java/hudson/AboutJenkins.java

 package hudson;
 
 import hudson.model.ManagementLink;
+import java.net.URL;
+import org.kohsuke.accmod.Restricted;
+import org.kohsuke.accmod.restrictions.NoExternalUse;
 
 /**
  * Show "About Jenkins" link.
@@ -27,4 +30,10 @@ public class AboutJenkins extends ManagementLink {
     public String getDescription() {
         return Messages.AboutJenkins_Description();
     }
+
+    @Restricted(NoExternalUse.class)
+    public URL getLicensesURL() {
+        return AboutJenkins.class.getResource("/META-INF/licenses.xml");
+    }
+
 }

core/src/main/resources/hudson/AboutJenkins/index.jelly

@@ -35,9 +35,17 @@ THE SOFTWARE.
       <p>
         ${%dependencies}
       </p>
-      <t:thirdPartyLicenses>
-        <st:include page="/META-INF/licenses.xml" optional="true" />
-      </t:thirdPartyLicenses>
+      <j:set var="uri" value="${it.licensesURL}"/>
+      <j:choose>
+          <j:when test="${uri != null}">
+              <t:thirdPartyLicenses>
+                  <j:include uri="${uri}"/>
+              </t:thirdPartyLicenses>
+          </j:when>
+          <j:otherwise>
+              <p>${%No information recorded}</p>
+          </j:otherwise>
+      </j:choose>
       <p>${%plugin.dependencies}</p>
       <ul>
           <j:forEach var="p" items="${app.pluginManager.plugins}"> <!-- XXX sort -->