Update dependencies to K8s 1.8

vendor/github.com/docker/distribution/digest/verifiers.go

@@ -1,44 +0,0 @@
-package digest
-
-import (
-	"hash"
-	"io"
-)
-
-// Verifier presents a general verification interface to be used with message
-// digests and other byte stream verifications. Users instantiate a Verifier
-// from one of the various methods, write the data under test to it then check
-// the result with the Verified method.
-type Verifier interface {
-	io.Writer
-
-	// Verified will return true if the content written to Verifier matches
-	// the digest.
-	Verified() bool
-}
-
-// NewDigestVerifier returns a verifier that compares the written bytes
-// against a passed in digest.
-func NewDigestVerifier(d Digest) (Verifier, error) {
-	if err := d.Validate(); err != nil {
-		return nil, err
-	}
-
-	return hashVerifier{
-		hash:   d.Algorithm().Hash(),
-		digest: d,
-	}, nil
-}
-
-type hashVerifier struct {
-	digest Digest
-	hash   hash.Hash
-}
-
-func (hv hashVerifier) Write(p []byte) (n int, err error) {
-	return hv.hash.Write(p)
-}
-
-func (hv hashVerifier) Verified() bool {
-	return hv.digest == NewDigest(hv.digest.Algorithm(), hv.hash)
-}