Update traefik dependencies (docker/docker and related) (#1823)

Update traefik dependencies (docker/docker and related)

- Update dependencies
- Fix compilation problems
- Remove vdemeester/docker-events (in docker api now)
- Remove `integration/vendor`
- Use `testImport`
- update some deps.
- regenerate the lock from scratch (after a `glide cc`)

vendor/github.com/docker/docker/client/volume_inspect.go

@@ -0,0 +1,38 @@
+package client
+
+import (
+	"bytes"
+	"encoding/json"
+	"io/ioutil"
+	"net/http"
+
+	"github.com/docker/docker/api/types"
+	"golang.org/x/net/context"
+)
+
+// VolumeInspect returns the information about a specific volume in the docker host.
+func (cli *Client) VolumeInspect(ctx context.Context, volumeID string) (types.Volume, error) {
+	volume, _, err := cli.VolumeInspectWithRaw(ctx, volumeID)
+	return volume, err
+}
+
+// VolumeInspectWithRaw returns the information about a specific volume in the docker host and its raw representation
+func (cli *Client) VolumeInspectWithRaw(ctx context.Context, volumeID string) (types.Volume, []byte, error) {
+	var volume types.Volume
+	resp, err := cli.get(ctx, "/volumes/"+volumeID, nil, nil)
+	if err != nil {
+		if resp.statusCode == http.StatusNotFound {
+			return volume, nil, volumeNotFoundError{volumeID}
+		}
+		return volume, nil, err
+	}
+	defer ensureReaderClosed(resp)
+
+	body, err := ioutil.ReadAll(resp.body)
+	if err != nil {
+		return volume, nil, err
+	}
+	rdr := bytes.NewReader(body)
+	err = json.NewDecoder(rdr).Decode(&volume)
+	return volume, body, err
+}