Use dockerCmd when possible (#14603)

- integration-cli/docker_cli_attach_test.go
- integration-cli/docker_cli_attach_unix_test.go
- integration-cli/docker_cli_build_test.go
- integration-cli/docker_cli_build_unix_test.go
- integration-cli/docker_cli_by_digest_test.go
- integration-cli/docker_cli_commit_test.go
- integration-cli/docker_cli_config_test.go
- integration-cli/docker_cli_cp_test.go
- integration-cli/docker_cli_create_test.go
- integration-cli/docker_cli_pause_test.go
- integration-cli/docker_cli_port_test.go
- integration-cli/docker_cli_port_unix_test.go
- integration-cli/docker_cli_proxy_test.go
- integration-cli/docker_cli_ps_test.go
- integration-cli/docker_cli_pull_test.go
- integration-cli/docker_cli_push_test.go

- docker_api_attach_test.go
- docker_api_containers_test.go
- docker_api_events_test.go
- docker_api_exec_resize_test.go
- docker_api_exec_test.go
- docker_api_images_test.go
- docker_api_info_test.go

Signed-off-by: Vincent Demeester <vincent@sbr.pm>

integration-cli/docker_cli_attach_test.go

@@ -76,10 +76,7 @@ func (s *DockerSuite) TestAttachMultipleAndRestart(c *check.C) {
 		c.Fatalf("Attaches did not initialize properly")
 	}
 
-	cmd := exec.Command(dockerBinary, "kill", "attacher")
-	if _, err := runCommand(cmd); err != nil {
-		c.Fatal(err)
-	}
+	dockerCmd(c, "kill", "attacher")
 
 	select {
 	case <-endDone:
@@ -90,11 +87,7 @@ func (s *DockerSuite) TestAttachMultipleAndRestart(c *check.C) {
 }
 
 func (s *DockerSuite) TestAttachTtyWithoutStdin(c *check.C) {
-	cmd := exec.Command(dockerBinary, "run", "-d", "-ti", "busybox")
-	out, _, err := runCommandWithOutput(cmd)
-	if err != nil {
-		c.Fatalf("failed to start container: %v (%v)", out, err)
-	}
+	out, _ := dockerCmd(c, "run", "-d", "-ti", "busybox")
 
 	id := strings.TrimSpace(out)
 	if err := waitRun(id); err != nil {