Updating for Jetty 9.2.2

+ Bumping jetty.version to 9.2.2.v20140723
+ Resetting Configuration.ATTR to null manually, as JettyOpenEJBModule
  needs to be control of it.
+ Manually calling WebAppContext.start() as the load order changes in
  Jetty 9.2.x prevent the reliance of default load order now.