Http Server: Modify the image in the testing

The testing require an image that contains java application to it can test the
java API. Now that the java based CLI is no longer supported the image that
will be used is jetty.

In addition, to simplify specific testing with and without ssl, make check was
broken in to two task check-ssl and check-http.

Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>
Http Server Test: switch from shutdown to power off

When running the tests, it is better to use power off to the running image, to
make sure that the tests would end.

Signed-off-by: Amnon Heiman <amnon@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>