In the postinstall script, if /etc/ld.so.conf is missing, the grep whines about it. Since it'll be created anyways if it's not there, you might consider doing: if [ ! -f /etc/ld.so.conf ]; then touch /etc/ld.so.conf fi before the grep.
This is fixed in krb5-1.2.1-10 and later in Raw Hide. Thanks!