Remove KEY, SIG, DNSKEY, RRSIG and NSEC records from LDAP schema.
These record types are either obsolete (KEY, SIG) or will be managed
automatically by BIND in memory and should never be read/stored from/to
database (DNSKEY, RRSIG, NSEC).
https://fedorahosted.org/bind-dyndb-ldap/ticket/56
Signed-off-by: Petr Spacek <pspacek@redhat.com>