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/libcompose/config/utils.go

@@ -0,0 +1,42 @@
+package config
+
+func merge(existing, value interface{}) interface{} {
+	// append strings
+	if left, lok := existing.([]interface{}); lok {
+		if right, rok := value.([]interface{}); rok {
+			return append(left, right...)
+		}
+	}
+
+	//merge maps
+	if left, lok := existing.(map[interface{}]interface{}); lok {
+		if right, rok := value.(map[interface{}]interface{}); rok {
+			newLeft := make(map[interface{}]interface{})
+			for k, v := range left {
+				newLeft[k] = v
+			}
+			for k, v := range right {
+				newLeft[k] = v
+			}
+			return newLeft
+		}
+	}
+
+	return value
+}
+
+func clone(in RawService) RawService {
+	result := RawService{}
+	for k, v := range in {
+		result[k] = v
+	}
+
+	return result
+}
+
+func asString(obj interface{}) string {
+	if v, ok := obj.(string); ok {
+		return v
+	}
+	return ""
+}