Update api documentation to add labels in commit

It is already possible to set labels at commit when using the API. But
it is not present in the API documentation. Added an integration test
too, to validate this work (and will be in the future).

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

integration-cli/docker_api_containers_test.go

@@ -725,6 +725,57 @@ func (s *DockerSuite) TestContainerApiCommit(c *check.C) {
 	}
 }
 
+func (s *DockerSuite) TestContainerApiCommitWithLabelInConfig(c *check.C) {
+	cName := "testapicommitwithconfig"
+	out, err := exec.Command(dockerBinary, "run", "--name="+cName, "busybox", "/bin/sh", "-c", "touch /test").CombinedOutput()
+	if err != nil {
+		c.Fatal(err, out)
+	}
+
+	config := map[string]interface{}{
+		"Labels": map[string]string{"key1": "value1", "key2": "value2"},
+	}
+
+	name := "TestContainerApiCommitWithConfig"
+	status, b, err := sockRequest("POST", "/commit?repo="+name+"&container="+cName, config)
+	c.Assert(status, check.Equals, http.StatusCreated)
+	c.Assert(err, check.IsNil)
+
+	type resp struct {
+		Id string
+	}
+	var img resp
+	if err := json.Unmarshal(b, &img); err != nil {
+		c.Fatal(err)
+	}
+
+	label1, err := inspectFieldMap(img.Id, "Config.Labels", "key1")
+	if err != nil {
+		c.Fatal(err)
+	}
+	c.Assert(label1, check.Equals, "value1")
+
+	label2, err := inspectFieldMap(img.Id, "Config.Labels", "key2")
+	if err != nil {
+		c.Fatal(err)
+	}
+	c.Assert(label2, check.Equals, "value2")
+
+	cmd, err := inspectField(img.Id, "Config.Cmd")
+	if err != nil {
+		c.Fatal(err)
+	}
+	if cmd != "{[/bin/sh -c touch /test]}" {
+		c.Fatalf("got wrong Cmd from commit: %q", cmd)
+	}
+
+	// sanity check, make sure the image is what we think it is
+	out, err = exec.Command(dockerBinary, "run", img.Id, "ls", "/test").CombinedOutput()
+	if err != nil {
+		c.Fatalf("error checking committed image: %v - %q", err, string(out))
+	}
+}
+
 func (s *DockerSuite) TestContainerApiCreate(c *check.C) {
 	config := map[string]interface{}{
 		"Image": "busybox",