Ticket 50260 - Invalid cache flushing improvements
Description: The original version of the fix only checked if backend
transaction "post" operation plugins failed, but it did
not check for errors from the backend transaction "pre"
operation plugin. To address this we flush invalid
entries whenever any error occurs.
We were also not flushing invalid cache entries when
modrdn errors occurred. Modrdns only make changes to
the DN hashtable inside the entry cache, but we were only
checking the ID hashtable. So we also need to check the
DN hashtable in the entry cache for invalid entries.
Reviewed by: firstyear & tbordaz(Thanks!!)