rebase: vendor golang.org/x/crypto and update to latest

The new SecretsMetadataKMS provider encrypts/decrypts DEKs as they are
stored in the metadata of volumes. The encryption/decryption uses
golang.org/x/crypto/scrypt to generate the encryption key from a
passphrase.

While vendoring golang.org/x/crypto, already vendored sub-packages have
been updated.

Signed-off-by: Niels de Vos <ndevos@redhat.com>

vendor/golang.org/x/term/term_plan9.go

@@ -0,0 +1,42 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package term
+
+import (
+	"fmt"
+	"runtime"
+
+	"golang.org/x/sys/plan9"
+)
+
+type state struct{}
+
+func isTerminal(fd int) bool {
+	path, err := plan9.Fd2path(fd)
+	if err != nil {
+		return false
+	}
+	return path == "/dev/cons" || path == "/mnt/term/dev/cons"
+}
+
+func makeRaw(fd int) (*State, error) {
+	return nil, fmt.Errorf("terminal: MakeRaw not implemented on %s/%s", runtime.GOOS, runtime.GOARCH)
+}
+
+func getState(fd int) (*State, error) {
+	return nil, fmt.Errorf("terminal: GetState not implemented on %s/%s", runtime.GOOS, runtime.GOARCH)
+}
+
+func restore(fd int, state *State) error {
+	return fmt.Errorf("terminal: Restore not implemented on %s/%s", runtime.GOOS, runtime.GOARCH)
+}
+
+func getSize(fd int) (width, height int, err error) {
+	return 0, 0, fmt.Errorf("terminal: GetSize not implemented on %s/%s", runtime.GOOS, runtime.GOARCH)
+}
+
+func readPassword(fd int) ([]byte, error) {
+	return nil, fmt.Errorf("terminal: ReadPassword not implemented on %s/%s", runtime.GOOS, runtime.GOARCH)
+}