Change KRB5KDC_ERR_NO_ACCEPTABLE_KDF to 100

draft-ietf-krb-wg-pkinit-alg-agility-07 specifies
KDC_ERR_NO_ACCEPTABLE_KDF as 82, but this value conflicts with
KRB_AP_ERR_PRINCIPAL_UNKNOWN from RFC 6111.  The former value has been
reassigned to 100 to fix the conflict.  Use the correct value.

We believe that this error won't crop up in practice for a long time
(when SHA-2 has been superceded by other hash algorithms and people
are desupporting it), by which time implementations will mostly have
been upgraded to use the new value.

ticket: 7715 (new)
target_version: 1.12