mustang only, on all platforms, in latest mustang promoted build

java plugin not downloading packed jars from server, even if we are hosting the packed jars using the JNLPDownloadServlet.

This is happening since we implemented the ResponseCache handler get and put method properly; now we are depending on the networking library to do the actual download for us, and we did not set the accept-encoding header properly, hence the servlet do not return the packed jars to us even if it is available