BUG #3660: unused empty file is created with csvlog

The following bug has been logged online:

Bug reference:      3660
Logged by:          Thomas Reiss
Email address:      thomas.reiss@interieur.gouv.fr
PostgreSQL version: 8.3 beta 1
Operating system:   Linux
Description:        unused empty file is created with csvlog
Details:

Hello,

I just tried the csvlog logging method.
I set the following :
log_destination = 'csvlog'
logging_collector = on
log_filename = 'postgresql-%u'

At server start, PostgreSQL creates a file called "postgresql-2" (for today)
and a file "postgresql-2.csv".
File "postgresql-2" is empty and never used again, whereas
"postgresql-2.csv" contains the logs.

If log_filename is set to 'postgresql-%u.csv', PostgreSQL creates two files
too: postgresql-2.csv and postgresql-2.csv.csv and uses the second one.

Regards,
Thomas