We might also ignore them, but if minCSN/contextCSN were not managed
properly, might as well make the effort to approach the actual value at
some point.

and make sure logfile_only doesn't mute failures to open logfile

The cache is again protected by a simple mutex and mp_children/mp_next
is protected by mp_mutex. Each monitor_send_children is called holding
the corresponding mp_mutex meaning the whole path from search base to
the current entry is off limits - cn=monitor searches cannot run in
parallel right now.

The code to initialize the TLS context was being bypassed by tool startup,
causing tools to get the wrong default setting. Move it earlier to avoid
being bypassed.

But skip calls to syslog() if logfile_only is set.