fixed a bug that prevented Hudson from working on Jetty.

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@976 71c3de6d-444a-0410-be80-ed276b4c234a

core/src/main/resources/hudson/model/JobCollection/index.jelly

 <j:jelly xmlns:j="jelly:core" xmlns:st="jelly:stapler" xmlns:d="jelly:define" xmlns:l="/lib/layout" xmlns:t="/lib/hudson" xmlns:f="/lib/form" xmlns:i="jelly:fmt">
-	<st:header name="X-Hudson" value="${servletContext.attribute['version']}" />
+	<st:header name="X-Hudson" value="${servletContext.getAttribute('version')}" />
   <j:new var="h" className="hudson.Functions" /><!-- instead of JSP functions -->
 	<l:layout title="${h.ifThenElse(app==it,'Dashboard',it.viewName)}">
 		<st:include page="sidepanel.jelly" />