After restarting the server nsslapd-mdb-max-dbs may not be high enough to add a new backend
because the value computation is wrong.
dbscan fails to open the database if nsslapd-mdb-max-dbs has been increased.
dbscan crashes when closing the database (typically when using -S)
When starting the instance the nsslapd-mdb-max-dbs parameter is increased to ensure that a new backend may be added.
When dse.ldif path is not specified, the db environment is now open using the INFO.mdb data instead of using the default values.
synchronization between thread closure and database context destruction is hardened
Several issues:
Issue: #6374
Reviewed by: @tbordaz , @vashirov (Thanks!)