Use new session entry points to get remote and user rather than dereference

the DCB directly.

server/include/session.h

@@ -150,6 +150,7 @@ bool    session_free(SESSION *);
 int	session_isvalid(SESSION *);
 int	session_reply(void *inst, void *session, GWBUF *data);
 char	*session_get_remote(SESSION *);
+char	*session_getUser(SESSION *);
 void	printAllSessions();
 void	printSession(SESSION *);
 void	dprintAllSessions(struct dcb *);