Ticket #47412 - Modify RUV should be serialized in ldbm_back_modify/add
Bug Description: Current ldbm_back_modify and _add allow RUV to
update without respecting other threads in the backend's critical
area. It gives a chance for 2 threads trying to modify RUV at the
same time in the 2 different transactions which causes the DB
deadlocks.
Fix Description: This patch changes the policy for RUV to skip
the backend serial lock.
https://fedorahosted.org/389/ticket/47412
Reviewed by Rich (Thank you!!)