Send logs from the linelog module to stdout

[work vlpl]

Hi, I am running radiusd in Docker container. In configuration
radiusd.conf I had set the user and group variable to drop permission
after the start. Radiusd process is started with `-fl stdout` to
redirect radiusd process logs to stdout and let Docker collect
necessary logs.
But in the linelog module if I will use /dev/stdout as filename
radiusd seems can't open it for writing. Also, Docker requires
`tty=true`, or permissions to /dev/stdout granted only to root. May I
ask if there is an option that I am missing, to redirect linelog
output to stdout?

Best regards,
Valdimir