update to use containerd seccomp package

Signed-off-by: Jess Frazelle <acidburn@microsoft.com>

vendor/github.com/docker/distribution/registry/handlers/mail.go

@@ -1,45 +0,0 @@
-package handlers
-
-import (
-	"errors"
-	"net/smtp"
-	"strings"
-)
-
-// mailer provides fields of email configuration for sending.
-type mailer struct {
-	Addr, Username, Password, From string
-	Insecure                       bool
-	To                             []string
-}
-
-// sendMail allows users to send email, only if mail parameters is configured correctly.
-func (mail *mailer) sendMail(subject, message string) error {
-	addr := strings.Split(mail.Addr, ":")
-	if len(addr) != 2 {
-		return errors.New("Invalid Mail Address")
-	}
-	host := addr[0]
-	msg := []byte("To:" + strings.Join(mail.To, ";") +
-		"\r\nFrom: " + mail.From +
-		"\r\nSubject: " + subject +
-		"\r\nContent-Type: text/plain\r\n\r\n" +
-		message)
-	auth := smtp.PlainAuth(
-		"",
-		mail.Username,
-		mail.Password,
-		host,
-	)
-	err := smtp.SendMail(
-		mail.Addr,
-		auth,
-		mail.From,
-		mail.To,
-		[]byte(msg),
-	)
-	if err != nil {
-		return err
-	}
-	return nil
-}