shadow: update to 4.20.2

shadow: update to 4.20.2

Refresh PKG_HASH from the release tarball.

Drop expiry, groupmems and logoutd from SHADOW_APPLETS: shadow 4.20
removed these applets (their sources are gone from the tarball and
src/Makefile.am no longer builds them), so shadow-expiry,
shadow-groupmems and shadow-logoutd have no binary to install.

Update the login.defs bcrypt sed: 4.20's etc/login.defs ships the
commented default "#ENCRYPT_METHOD SHA512" instead of
"#ENCRYPT_METHOD DES", so the old pattern matched nothing and left
ENCRYPT_METHOD unset.

Refresh 004-fix-su-controoling-term.patch for the shifted su.c line
numbers and add the missing git-am header.

Signed-off-by: Alexandru Ardelean <redacted>