Improve kadm5.acl bug fix.

share/debian-edu-config/tools/kerberos-kdc-init:
Also disable inquiries to the Kerberos database for ordinary users.

debian/debian-edu-config.postinst:
Restart krb5-admin-server if the fix gets applied via upgrades.

Signed-off-by: Wolfgang Schweer <wschweer@arcor.de>