5.0.2 无法优雅关机

- [ ] I have searched the [issues](https://github.com/codingapi/tx-lcn/issues) of this repository and believe that this is not a duplicate.

### 1. Bug Description
程序在停机时（`kill PID`），会断开与tm的netty链接，但是链接断开后又会引起重连，因此引发无法优雅关机，最后不得不使用 `kill -9 PID` 的方式来强杀

### 2. Environment:
- JDK version:1.8
- OS:win10
- TX-LCN version:5.0.2
- Others:

### 3. Exception Stacktrace

```
[2019-08-01 10:18:01.480] [nioEventLoopGroup-5-3] [ERROR] io.netty.util.concurrent.DefaultPromise.rejectedExecution [181] - Failed to submit a listener notification task. Event loop shut down?
java.util.concurrent.RejectedExecutionException: event executor terminated
at io.netty.util.concurrent.SingleThreadEventExecutor.reject(SingleThreadEventExecutor.java:842)
at io.netty.util.concurrent.SingleThreadEventExecutor.offerTask(SingleThreadEventExecutor.java:328)
at io.netty.util.concurrent.SingleThreadEventExecutor.addTask(SingleThreadEventExecutor.java:321)
at io.netty.util.concurrent.SingleThreadEventExecutor.execute(SingleThreadEventExecutor.java:765)
at io.netty.util.concurrent.DefaultPromise.safeExecute(DefaultPromise.java:768)
at io.netty.util.concurrent.DefaultPromise.notifyListeners(DefaultPromise.java:432)
at io.netty.util.concurrent.DefaultPromise.trySuccess(DefaultPromise.java:103)
at io.netty.channel.DefaultChannelPromise.trySuccess(DefaultChannelPromise.java:84)
at io.netty.channel.AbstractChannel$CloseFuture.setClosed(AbstractChannel.java:1148)
at io.netty.channel.AbstractChannel$AbstractUnsafe.register(AbstractChannel.java:490)
at io.netty.channel.SingleThreadEventLoop.register(SingleThreadEventLoop.java:80)
at io.netty.channel.SingleThreadEventLoop.register(SingleThreadEventLoop.java:74)
at io.netty.channel.MultithreadEventLoopGroup.register(MultithreadEventLoopGroup.java:86)
at io.netty.bootstrap.AbstractBootstrap.initAndRegister(AbstractBootstrap.java:333)
at io.netty.bootstrap.Bootstrap.doResolveAndConnect(Bootstrap.java:163)
at io.netty.bootstrap.Bootstrap.connect(Bootstrap.java:145)
at com.codingapi.txlcn.txmsg.netty.impl.NettyRpcClientInitializer.connect(NettyRpcClientInitializer.java:109)
at com.codingapi.txlcn.txmsg.netty.impl.NettyRpcClientInitializer.reConnect(NettyRpcClientInitializer.java:76)
at com.codingapi.txlcn.txmsg.netty.handler.NettyClientRetryHandler.channelInactive(NettyClientRetryHandler.java:79)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:245)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:231)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelInactive(AbstractChannelHandlerContext.java:224)
at io.netty.channel.ChannelInboundHandlerAdapter.channelInactive(ChannelInboundHandlerAdapter.java:75)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:245)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:231)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelInactive(AbstractChannelHandlerContext.java:224)
at io.netty.channel.ChannelInboundHandlerAdapter.channelInactive(ChannelInboundHandlerAdapter.java:75)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:245)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:231)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelInactive(AbstractChannelHandlerContext.java:224)
at io.netty.handler.codec.ByteToMessageDecoder.channelInputClosed(ByteToMessageDecoder.java:377)
at io.netty.handler.codec.ByteToMessageDecoder.channelInactive(ByteToMessageDecoder.java:342)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:245)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:231)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelInactive(AbstractChannelHandlerContext.java:224)
at io.netty.channel.DefaultChannelPipeline$HeadContext.channelInactive(DefaultChannelPipeline.java:1429)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:245)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:231)
at io.netty.channel.DefaultChannelPipeline.fireChannelInactive(DefaultChannelPipeline.java:947)
at io.netty.channel.AbstractChannel$AbstractUnsafe$8.run(AbstractChannel.java:822)
at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:163)
at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasksFrom(SingleThreadEventExecutor.java:380)
at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:355)
at io.netty.util.concurrent.SingleThreadEventExecutor.confirmShutdown(SingleThreadEventExecutor.java:701)
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:456)
at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:884)
at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
at java.lang.Thread.run(Thread.java:745)

```

### 4. Tour Idea