Switch java recommendation to suggests

In essence, Berkshelf will always download a recommends but not a suggests. Our org uses a separate Java cookbook, so the version pin here presents a bit of a problem, and in some cases, we trust that the AMI we build off of will have Java. So in order to appease Berkshelf but still make Java a known system requirement, bumping this down to suggests means other orgs can not be dependent on the community Java cookbook.