Improve user name setting in DCB for persistent connections and to fix bug; change name of session_alloc_dummy to session_set_dummy to be more informative.

server/core/session.c

@@ -222,7 +222,7 @@ session_alloc(SERVICE *service, DCB *client_dcb)
  * @return		The dummy created session
  */
 SESSION *
-session_alloc_dummy(DCB *client_dcb)
+session_set_dummy(DCB *client_dcb)
 {
     SESSION 	*session;