Fix the shutdown.jar assembly

AS trunk shutdown.sh leads to:

Exception in thread "main" java.lang.NoClassDefFoundError: org/jboss/Shutdown
Caused by: java.lang.ClassNotFoundException: org.jboss.Shutdown
at java.net.URLClassLoader$1.run(URLClassLoader.java:200)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
at java.lang.ClassLoader.loadClass(ClassLoader.java:252)
at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:320)
Could not find the main class: org.jboss.Shutdown. Program will exit.

Fix the assembly to ensure all required classes are accounted for