Tracer-TimedAppender thread should set daemon

[leizhiyuan]

sofastack/sofa-rpc-boot-projects#69

from the issue, I tested on the local machine

 SofaTracerStatisticReporterManager(final long cycleTime) {
        this.cycleTime = cycleTime;
        this.executor = Executors.newSingleThreadScheduledExecutor(new ThreadFactory() {

            public Thread newThread(Runnable r) {
                final Thread thread = new Thread(r, "Tracer-TimedAppender-"
                                                    + THREAD_NUMBER.incrementAndGet() + "-"
                                                    + cycleTime);
                thread.setDaemon(true);
                return thread;
            }
        });
        start();
    }

this code should modify like this