Add to default fai.conf

[Per Foreby]

When running a softupdate, two variables must be added to fai.conf:
monserver for faimond, and LOGSERVER to copy the logs to the server.

It would be nice if these variables were added to the default 
fai.conf so it is obvious that they have to be defined.

Even better would be if they weren't needed. Both logs and monitoring 
works when doing the initial install, so I don't see any reason why it 
shouldn't work on softupdates.

/Per