Update netty-build to the latest version

From this commit, checkstyle considers an unnecessary empty line as a
violation.

example/src/main/java/io/netty/example/filetransfer/FileServer.java

@@ -101,7 +101,6 @@ public class FileServer {
                 ctx.write(file + " " + file.length() + "\n");
                 ctx.sendFile(new DefaultFileRegion(new FileInputStream(file).getChannel(), 0, file.length()));
                 ctx.write("\n");
-
             } else {
                 ctx.write("File not found: " + file + "\n");
             }

pom.xml

@@ -330,7 +330,7 @@
           <dependency>
             <groupId>${project.groupId}</groupId>
             <artifactId>netty-build</artifactId>
-            <version>12</version>
+            <version>13</version>
           </dependency>
         </dependencies>
       </plugin>

transport/src/main/java/io/netty/channel/AbstractChannel.java

@@ -393,8 +393,6 @@ public abstract class AbstractChannel extends DefaultAttributeMap implements Cha
         return strVal;
     }
 
-
-
     protected abstract class AbstractUnsafe implements Unsafe {
 
         private final class FlushTask {
@@ -446,11 +444,9 @@ public abstract class AbstractChannel extends DefaultAttributeMap implements Cha
                         }
                     });
                 } else {
-
                     // nothing pending try to send the fileRegion now!
                     sendFile0(region, future);
                 }
-
             } else {
                 eventLoop().execute(new Runnable() {
                     @Override
@@ -736,7 +732,6 @@ public abstract class AbstractChannel extends DefaultAttributeMap implements Cha
                     return;
                 }
                 flushNotifierAndFlush(future);
-
             } else {
                 eventLoop().execute(new Runnable() {
                     @Override

transport/src/main/java/io/netty/channel/Channel.java

@@ -278,6 +278,5 @@ public interface Channel extends AttributeMap, ChannelOutboundInvoker, ChannelPr
         void resumeRead();
 
         void sendFile(FileRegion region, ChannelFuture future);
-
     }
 }

transport/src/main/java/io/netty/channel/socket/aio/AioSocketChannel.java

@@ -565,7 +565,6 @@ public class AioSocketChannel extends AbstractAioChannel implements SocketChanne
                 @Override
                 public void completed(Integer result, Object attachment) {
                     try {
-
                         if (result == 0) {
                             javaChannel().write(src, null, this);
                             return;

transport/src/main/java/io/netty/channel/socket/nio/AbstractNioByteChannel.java

@@ -109,7 +109,6 @@ abstract class AbstractNioByteChannel extends AbstractNioChannel {
         }
     }
 
-
     @Override
     protected void doFlushByteBuffer(ByteBuf buf) throws Exception {
         if (!buf.readable()) {
@@ -131,7 +130,6 @@ abstract class AbstractNioByteChannel extends AbstractNioChannel {
         }
     }
 
-
     @Override
     protected void doFlushFileRegion(final FileRegion region, final ChannelFuture future) throws Exception {
         if (javaChannel() instanceof WritableByteChannel) {

transport/src/main/java/io/netty/channel/socket/nio/NioEventLoop.java

@@ -128,7 +128,6 @@ public final class NioEventLoop extends SingleThreadEventLoop {
         }
     }
 
-
     void executeWhenWritable(AbstractNioChannel channel, NioTask<? extends SelectableChannel> task) {
         if (channel == null) {
             throw new NullPointerException("channel");
@@ -141,7 +140,6 @@ public final class NioEventLoop extends SingleThreadEventLoop {
         SelectionKey key = channel.selectionKey();
         channel.writableTasks.offer((NioTask<SelectableChannel>) task);
         key.interestOps(key.interestOps() | SelectionKey.OP_WRITE);
-
     }
 
     // Create a new selector and "transfer" all channels from the old

transport/src/main/java/io/netty/channel/socket/oio/OioSocketChannel.java

@@ -253,6 +253,5 @@ public class OioSocketChannel extends AbstractOioByteChannel
                 return;
             }
         }
-
     }
 }