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/config_update.go

@@ -0,0 +1,18 @@
+package client
+
+import (
+	"net/url"
+	"strconv"
+
+	"github.com/docker/docker/api/types/swarm"
+	"golang.org/x/net/context"
+)
+
+// ConfigUpdate attempts to update a Config
+func (cli *Client) ConfigUpdate(ctx context.Context, id string, version swarm.Version, config swarm.ConfigSpec) error {
+	query := url.Values{}
+	query.Set("version", strconv.FormatUint(version.Index, 10))
+	resp, err := cli.post(ctx, "/configs/"+id+"/update", query, config, nil)
+	ensureReaderClosed(resp)
+	return err
+}