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`)

integration/vendor/github.com/libkermit/docker-check/images.go

@@ -1,11 +0,0 @@
-package docker
-
-import (
-	"github.com/go-check/check"
-)
-
-// Pull pulls the given reference (image)
-func (p *Project) Pull(c *check.C, ref string) {
-	c.Assert(p.project.Pull(ref), check.IsNil,
-		check.Commentf("Error while pulling image %s: %s", ref))
-}