Move engine-api client package

This moves the engine-api client package to `/docker/docker/client`.

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

client/volume_create.go

@@ -0,0 +1,20 @@
+package client
+
+import (
+	"encoding/json"
+
+	"github.com/docker/docker/api/types"
+	"golang.org/x/net/context"
+)
+
+// VolumeCreate creates a volume in the docker host.
+func (cli *Client) VolumeCreate(ctx context.Context, options types.VolumeCreateRequest) (types.Volume, error) {
+	var volume types.Volume
+	resp, err := cli.post(ctx, "/volumes/create", nil, options, nil)
+	if err != nil {
+		return volume, err
+	}
+	err = json.NewDecoder(resp.body).Decode(&volume)
+	ensureReaderClosed(resp)
+	return volume, err
+}