The following commit introduced a defect "13089: Dereference after null
check".
commit b37e0c2e878ecef8c46449ce4e44a3c0deb344f2
Author: Noriko Hosoi <nhosoi at redhat.com>
Date: Tue Aug 28 17:28:59 2012 -0700
Trac Ticket #437 - variable dn should not be used in ldbm_back_delete