Ticket 50370 - CleanAllRUV task crashing during server shutdown
Description: There is a race condition during server shutdown that
can cause the server to crash. Increment the active
thread count for each cleaning task to prevent the plugins
from being closed before the thread terminates.
https://pagure.io/389-ds-base/issue/50370
Reviewed by: firstyear(Thanks!)
(cherry picked from commit 7141b8d10382e8dcb8528b57e5226c82506b79b9)