Bump to Java 7u15. Use `curl` with a cookie to overcome oracle.com difficulty.

I learned the trick for directly downloading Oracle’s JDK from [this post](http://blog.kdecherf.com/2012/04/12/oracle-i-download-your-jdk-by-eating-magic-cookies/).

I am a complete puppet newb, so maybe there’s a better way to get that cookie onto the request.

Thanks for groovy software!