Fix Config.Cpuset from API < 1.20

Signed-off-by: Antonio Murdaca <amurdaca@redhat.com>

integration-cli/docker_api_inspect_unix_test.go

@@ -0,0 +1,38 @@
+// +build !windows
+
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+
+	"github.com/go-check/check"
+)
+
+// #16665
+func (s *DockerSuite) TestInspectApiCpusetInConfigPre120(c *check.C) {
+	testRequires(c, DaemonIsLinux)
+	testRequires(c, cgroupCpuset)
+
+	name := "cpusetinconfig-pre120"
+	dockerCmd(c, "run", "--name", name, "--cpuset", "0-1", "busybox", "true")
+
+	status, body, err := sockRequest("GET", fmt.Sprintf("/v1.19/containers/%s/json", name), nil)
+	c.Assert(status, check.Equals, http.StatusOK)
+	c.Assert(err, check.IsNil)
+
+	var inspectJSON map[string]interface{}
+	if err = json.Unmarshal(body, &inspectJSON); err != nil {
+		c.Fatalf("unable to unmarshal body for version 1.19: %v", err)
+	}
+
+	config, ok := inspectJSON["Config"]
+	if !ok {
+		c.Fatal("Unable to find 'Config'")
+	}
+	cfg := config.(map[string]interface{})
+	if _, ok := cfg["Cpuset"]; !ok {
+		c.Fatal("Api version 1.19 expected to include Cpuset in 'Config'")
+	}
+}