BUG #2760: log_min_duration_statement always logs to stderr

The following bug has been logged online:

Bug reference: 2760
Logged by: Jonathan Ellis
Email address: jonathan@utahpython.org
PostgreSQL version: 8.1
Operating system: Linux (debian)
Description: log_min_duration_statement always logs to stderr
Details:

I expected that log_destination = 'syslog' would result in this only going
to syslog, but it goes to both.