samba: Use built in kerberos

Changed files
+2 -1
pkgs
top-level
+2 -1
pkgs/top-level/all-packages.nix
···
samba4 = callPackage ../servers/samba/4.x.nix {
python = python2;
-
kerberos = libheimdal;
+
# Samba is tightly coupled to kerberos so let it provide its own
+
kerberos = null;
gnutls = gnutls33;
cups = if stdenv.isDarwin then null else cups;
pam = if stdenv.isDarwin then null else pam;