Close connection in case of unexpected exception in Drift server

Otherwise the clients may be hanging forever, as the connection may be
no longer in a consistent state

drift-transport-netty/src/main/java/io/airlift/drift/transport/netty/server/ThriftServerHandler.java

@@ -102,6 +102,7 @@ public void channelRead(ChannelHandlerContext context, Object message)
     @Override
     public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause)
     {
+        ctx.close();
         // Don't log connection closed exceptions
         if (!isConnectionClosed(cause)) {
             log.error(cause);