Quoting Dan White <dwhite(a)olp.net>:
You could direct your syslog daemon to ignore those messages.
Look for lines which include:
I don't use syslogd, I run socklog-unix and socklog-klog services
which are running under svlogd and listen directly to the OS's
standard logging socket. I don't want to wholesale discount local4
messages because they might come from something else than slapd
running in the foreground.