Fix nsslapd-db-lock tuning of BDB backend
    
    nsslapd-db-lock was moved from cn=config,cn=ldbm database,cn=plugins,cn=config
    entry to cn=bdb subentry. Manual patching of dse.ldif was no longer
    working. Installations with 389-DS 1.4.3 and newer are affected.
    
    Low lock count can affect performance during high load, e.g. mass-import
    of users or lots of concurrent connections.
    
    Bump minimal DS version to 1.4.3. Fedora 32 and RHEL 8.3 have 1.4.3.
    
    Fixes: https://pagure.io/freeipa/issue/8515
    See: https://pagure.io/freeipa/issue/5914
    Signed-off-by: Christian Heimes <cheimes@redhat.com>
    Reviewed-By: Francois Cami <fcami@redhat.com>
    Reviewed-By: Francois Cami <fcami@redhat.com>