openldap: slapd crash on modrdn operation with NOOP control on entry in bdb storage

slapd/back-bdb/modrdn.c in the BDB backend for slapd in OpenLDAP 2.3.39 allows remote authenticated users to cause a denial of service daemon crash via a modrdn operation with a NOOP LDAPXNOOPERATION control, a related issue to CVE-2007-6698...