Clients using SecurityClientFactory are not authenticated when using Elytron

Clients using org.jboss.security.client.SecurityClientFactory are not authenticated when Elytron security is used on the server.

For instance if a servlet authenticates to call a protected EJB:

SecurityClient client = SecurityClientFactory.getSecurityClient();
client.setSimple("user", "password");
client.login();
ejb.callProtectedMethod();
// ...

Clients with such code don't work with Elytron, which makes easy application migration to Elytron impossible.

Setting priority to blocker as we need to provide a simple migration way.