Ticket 47619: cannot reindex retrochangelog
Bug Description:
An index task (through db2index.pl) on changelog backend may hang.
The reason is that the retrocl-plugin start function (retrocl_start) acquires the
changelog backend in read (slapi_be_Rlock) but does not release it.
The task will try to acquire it in Write but will wait indefinitely.
Fix Description:
Make retrocl_start to release the lock acquired in Read in slapi_mapping_tree_select
https://fedorahosted.org/389/ticket/47619
Reviewed by: Rich Megginson
Platforms tested: F17
Flag Day: no
Doc impact: no
(cherry picked from commit 8087f058cd9acc304de351412742fd8ceb3ceb48)