Why is log.smbd created even though the value of "log file" is not log.%m?

Issue

• Why is log.smbd created even though the value of "log file" is not log.%m?

smb.conf
--------
log file = /var/log/samba/%m.log

When smbd starts, /var/log/samba/log.smbd is created:

# cat /var/log/samba/log.smbd 
[2014/02/18 10:03:38,  0] smbd/server.c:1026(main)
  smbd version 3.6.9-164.el6 started.
  Copyright Andrew Tridgell and the Samba Team 1992-2011