kola/test:docker: Prepare for replacing ncat with openbsd nc

OpenBSD netcat has no long flags and has no idle timeout flag (there
is some timeout flag, -w, but it's ignored in listening mode). The
timeout flag is no problem in the end, as the whole test has a timeout
of one minute anyway.

kola/tests/docker/docker.go

@@ -367,15 +367,15 @@ func dockerNetwork(c cluster.TestCluster) {
 	machines := c.Machines()
 	src, dest := machines[0], machines[1]
 
-	c.Log("creating ncat containers")
+	c.Log("creating netcat containers")
 
-	GenDockerImage(c, src, "ncat", []string{"ncat"})
-	GenDockerImage(c, dest, "ncat", []string{"ncat"})
+	GenDockerImage(c, src, "netcat", []string{"nc"})
+	GenDockerImage(c, dest, "netcat", []string{"nc"})
 
 	listener := func(ctx context.Context) error {
-		// Will block until a message is recieved
+		// Will block until a message is received
 		out, err := c.SSH(dest,
-			`echo "HELLO FROM SERVER" | docker run -i -p 9988:9988 ncat ncat --idle-timeout 20 --listen 0.0.0.0 9988`,
+			`echo "HELLO FROM SERVER" | docker run -i -p 9988:9988 netcat nc -l 0.0.0.0 9988`,
 		)
 		if err != nil {
 			return err
@@ -409,7 +409,7 @@ func dockerNetwork(c cluster.TestCluster) {
 			}
 		}
 
-		srcCmd := fmt.Sprintf(`echo "HELLO FROM CLIENT" | docker run -i ncat ncat %s 9988`, dest.PrivateIP())
+		srcCmd := fmt.Sprintf(`echo "HELLO FROM CLIENT" | docker run -i netcat nc %s 9988`, dest.PrivateIP())
 		out, err := c.SSH(src, srcCmd)
 		if err != nil {
 			return err