The actual copyright notices say only the documentation is licensed under CC-BY-SA-3.0 terms.
This is the only non-free element required for Samba 4.x at the moment.
I believe this can be fixed simply by changing the LICENSE line as follows:
LICENSE="openafs-krb5-a BSD MIT OPENLDAP BSD-2 HPND BSD-4 ISC RSA doc? ( CC-BY-SA-3.0 ) || ( BSD-2 GPL-2+ )"
However, mit-krb5 seems to unconditionally install man pages and conf files examples, so making one or both of these conditional might also be necessary.