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.go

@@ -0,0 +1,58 @@
+// 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 provides support functions for dealing with terminals, as
+// commonly found on UNIX systems.
+//
+// Putting a terminal into raw mode is the most common requirement:
+//
+// 	oldState, err := terminal.MakeRaw(0)
+// 	if err != nil {
+// 	        panic(err)
+// 	}
+// 	defer terminal.Restore(0, oldState)
+package term
+
+// State contains the state of a terminal.
+type State struct {
+	state
+}
+
+// IsTerminal returns whether the given file descriptor is a terminal.
+func IsTerminal(fd int) bool {
+	return isTerminal(fd)
+}
+
+// MakeRaw puts the terminal connected to the given file descriptor into raw
+// mode and returns the previous state of the terminal so that it can be
+// restored.
+func MakeRaw(fd int) (*State, error) {
+	return makeRaw(fd)
+}
+
+// GetState returns the current state of a terminal which may be useful to
+// restore the terminal after a signal.
+func GetState(fd int) (*State, error) {
+	return getState(fd)
+}
+
+// Restore restores the terminal connected to the given file descriptor to a
+// previous state.
+func Restore(fd int, oldState *State) error {
+	return restore(fd, oldState)
+}
+
+// GetSize returns the visible dimensions of the given terminal.
+//
+// These dimensions don't include any scrollback buffer height.
+func GetSize(fd int) (width, height int, err error) {
+	return getSize(fd)
+}
+
+// ReadPassword reads a line of input from a terminal without local echo.  This
+// is commonly used for inputting passwords and other sensitive data. The slice
+// returned does not include the \n.
+func ReadPassword(fd int) ([]byte, error) {
+	return readPassword(fd)
+}