BUG #7528: Spurious empty log file created

The following bug has been logged on the website:

Bug reference:      7528
Logged by:          Alexander Jerusalem
Email address:      ajeru@topolyte.com
PostgreSQL version: 9.2.0
Operating system:   Linux (Ubuntu x86_64, kernel version 2.6.18)
Description:        =


I have the following log configuration in postgresql.conf:

log_destination =3D 'csvlog'
logging_collector =3D on
log_directory =3D 'pg_log'
log_filename =3D 'pg-%Y-%m-%d_%H%M%S.log'
log_rotation_age =3D 1d
log_rotation_size =3D 10MB

After removing all files from pg_log and relaunching the postgres server,
pg_log contains two files instead of one: pg-xxx.log and pg-xxx.csv.
According to the documentation, only pg-xxx.csv should exist. And in fact
only pg-xxx.csv is actually written to whilst pg-xxx.log remains empty.

Using a .csv extenson or no extension at all for the log_filename setting
doesn't help either. Postgres always creates a file named exactly as the
log_filename setting says and a second one with .csv appended.