Ticket 47396 - crash on modrdn of tombstone
Bug Description: a client modrdn operation on a tombstone entry can crash the server
Fix Description: client modrdns and modifies on tombstone entries should not be
accepted. Tombstones aer internally kept for eventual conflict resolution, normal
clients should not touch them.
an exception would be to force purging of tombstones or a kind of "undo" for
a delete, which could resurrect a tombstone, but this is not in the scope of this ticket
https://fedorahosted.org/389/ticket/47396
Reviewed by: Rich, thanks
(cherry picked from commit d1d6245d6ab894cf56e2529cb5c5dc941f4843cd)