This problem has been reported several times in the past. The settings in the nsd.tcl file make no difference. Which leads me to belief that there is a bug in the ns_log command.
However, you can turn of the QD logging by commenting out the following ns_log line in packages/acs-bootstrap-installer/tcl/40-db-query-dispatcher-procs.tcl:
proc db_qd_log {level msg} {
# Centralized DB QD logging
# We switch everything to debug for now
# ns_log $level "QD_LOGGER = $msg"
}