A proxy LoginModule that loads a delegate LoginModule using
the current thread context class loader. The purpose of this
module is to work around the current JAAS class loader limitation
that requires LoginModules to be on the classpath. Some LoginModules
use core JBoss classes that would have to be moved into the jboss-jaas.jar
and packaging becomes a mess. Instead, these LoginModules are left
in the jbosssx.jar and the ProxyLoginModule is used to bootstrap
the non-classpath LoginModule.