correct passes the header to jenkins and upgrade jetty's version

## Description of your patch

- fixing the jenkins link issues
- upgrade jetty to last stable version


## Estimated risk

Low

## Components involved

Jetty, Nginx

## Description of testing done

Creating an environment which be installed jenkins, and then access jenkins url and click "Manage Jenkins" and do browser back.

## QA Instructions

- To create an environment and upload and apply the recipes with including "jenkins recipe"
https://github.com/engineyard/ey-cloud-recipes/blob/master/cookbooks/jenkins/README.md