If no Kerberos is wanted (MK_KERBEROS == no) remove whatever kerberos
is installed.
If MIT KRB5 is wanted (MK_MITKRB5 == yes) remove the Heimdal files.
If Heimdal is wanted (MK_MITKRB5 == no) remove the MIT KRB5 files.
Sponsored by: The FreeBSD Foundation