Remove redundant "close" call

Closing the resource is handled automatically by the try-with-resources.

Closes gh-12453

spring-boot-project/spring-boot-devtools/src/main/java/org/springframework/boot/devtools/tunnel/client/TunnelClient.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2017 the original author or authors.
+ * Copyright 2012-2018 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -179,7 +179,6 @@ public class TunnelClient implements SmartInitializingSingleton {
 					ByteBuffer buffer = ByteBuffer.allocate(BUFFER_SIZE);
 					int amountRead = socketChannel.read(buffer);
 					if (amountRead == -1) {
-						outputChannel.close();
 						return;
 					}
 					if (amountRead > 0) {