Fix gh#7747 - filter bare newline output and log client pull to stdout

Docker-DCO-1.1-Signed-off-by: Phil Estes <estesp@linux.vnet.ibm.com> (github: estesp)

api/client/commands.go

@@ -1993,7 +1993,7 @@ func (cli *DockerCli) pullImage(image string) error {
 	registryAuthHeader := []string{
 		base64.URLEncoding.EncodeToString(buf),
 	}
-	if err = cli.stream("POST", "/images/create?"+v.Encode(), nil, cli.err, map[string][]string{"X-Registry-Auth": registryAuthHeader}); err != nil {
+	if err = cli.stream("POST", "/images/create?"+v.Encode(), nil, cli.out, map[string][]string{"X-Registry-Auth": registryAuthHeader}); err != nil {
 		return err
 	}
 	return nil

utils/jsonmessage.go

@@ -143,7 +143,9 @@ func DisplayJSONMessagesStream(in io.Reader, out io.Writer, terminalFd uintptr,
 			if !ok {
 				line = len(ids)
 				ids[jm.ID] = line
-				fmt.Fprintf(out, "\n")
+				if isTerminal {
+					fmt.Fprintf(out, "\n")
+				}
 				diff = 0
 			} else {
 				diff = len(ids) - line