update on chap-rf

[Pierre-Philipp Braun <pbraun%nethence.com@localhost>]

Hi,

I am glad to send something to the documentation team.  The very good 
Raidframe chapter needs a few updates.

- installboot timeout is used as a trick to quicly identify on what disk 
the system is going to boot.  You need to remove the /boot.cfg to use 
the legacy bootloader layout, as /boot.cfg also has a timeout parameter 
which takes precedence.  Either edit /boot.cfg or remove it.  I like the 
old boot menu so I do,
        /usr/sbin/installboot -o timeout=20 -v /dev/rwd1a \
        /usr/mdec/bootxx_ffsv2
        mv /boot.cfg /boot.cfg.bkp
Note. This applies to the several installboot occurrences in the guide.

- There is a little confusion on using FFSv1 versus FFSv2.  First the 
guide says to initialize the file system on raid0a with FFSv1.  Then is 
uses installboot to install the FFSv2 boot blocks.  Then the note just 
below the latter explains it all.  Well, using FFSv2 from the start 
isn't a bit issue even on less that 1TB drives.  It worked fine here, 
anyways.  I guess you should just use FFSv2 from the start, and add a 
little note on using FFSv1 for older systems.  The note just below 
installboot could stay unchanged.

Best regards
Pierre-Philipp