sudo: Add missing dep on virtual/crypt

sudo: Add missing dep on virtual/crypt

Ensure we have virtual/crypt even if building without PAM; fixes:

  sudo: error in /etc/sudo.conf, line 0 while loading plugin "sudoers_policy"
  sudo: unable to load /usr/libexec/sudo/sudoers.so: /usr/libexec/sudo/sudoers.so: undefined symbol: crypt
  sudo: fatal error, unable to load plugins

Signed-off-by: Alex Kiernan <alex.kiernan@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>