Fixed code smells

cmd/protodial/main.go

@@ -40,16 +40,16 @@ func main() {
 
 	c = protocol.Limit(c, func(dir protocol.Direction, p *protocol.Protocol) error {
 		if p == nil {
-			return errors.New("No protocol detected")
+			return errors.New("no protocol detected")
 		}
 		if !accept[p.Name] {
-			return fmt.Errorf("Protocol %s is not accepted", p.Name)
+			return fmt.Errorf("protocol %s is not accepted", p.Name)
 		}
 		fmt.Fprintf(os.Stderr, "Accepting protocol %s version %s initiated by %s\n",
 			p.Name, p.Version, dir)
 		return nil
 	})
-	defer c.Close()
+	defer func() { _ = c.Close() }()
 
 	var wait sync.WaitGroup
 	wait.Go(func() { multiplex(c, os.Stdin) })

cmd/protoproxy/main.go

@@ -72,8 +72,8 @@ func proxy(client net.Conn, target string) {
 	// Create a wait group and copy between client and server bidirectionally,
 	// either side needs to generate data for the detection to work.
 	var group sync.WaitGroup
-	group.Go(func() { io.Copy(client, server) })
-	group.Go(func() { io.Copy(server, client) })
+	group.Go(func() { _, _ = io.Copy(client, server) })
+	group.Go(func() { _, _ = io.Copy(server, client) })
 
 	// Wait until the interceptor produces data.
 	result := <-intercepted