Ticket - 49623-cont cenotaph errors on modrdn operations
Bug: In modrdn operations a cenotaph entries are created to track the time when
an entry had existed. But in cases where rentries were renamed in cycles
reusing the dns again and again this failed with an error: "faild to add cenotaph"
Fix: Previous versions of cenotaphs with the same dn are not used (or maybe in very unlikely
scenarios) so there is no need to change the dn construction to be able to keep all
versions of the same cenotaph. Instead, if the creation of the cenotaph fails because
it already exists, the existin cenotaph is moodified with the lifespan data of the
cenotaph that was tried to add.
Reviewed by: Thierry, thanks