Integrated json-lib 2.4

I had to tweak UpdateSite code because JSONObject.fromObject(String)
became more strict and no longer allows extra garbage after the closing
'}'

core/pom.xml

@@ -199,7 +199,7 @@ THE SOFTWARE.
     <dependency><!-- until we get this version through Stapler -->
       <groupId>org.kohsuke.stapler</groupId>
       <artifactId>json-lib</artifactId>
-      <version>2.1-rev7</version>
+      <version>2.4-jenkins-1</version>
     </dependency>
     <dependency>
       <groupId>commons-httpclient</groupId>

core/src/main/java/hudson/model/UpdateSite.java

@@ -171,7 +171,11 @@ public class UpdateSite {
                         String uncleanJson = IOUtils.toString(is,"UTF-8");
                         int jsonStart = uncleanJson.indexOf("{\"");
                         if (jsonStart >= 0) {
-                            return updateData(uncleanJson.substring(jsonStart), signatureCheck);
+                            uncleanJson = uncleanJson.substring(jsonStart);
+                            int end = uncleanJson.lastIndexOf('}');
+                            if (end>0)
+                                uncleanJson = uncleanJson.substring(0,end+1);
+                            return updateData(uncleanJson, signatureCheck);
                         } else {
                             throw new IOException("Could not find json in content of " +
                             		"update center from url: "+src.toExternalForm());