experience updating current -> current with sysinst

[Hubert Feyrer <hubert%feyrer.de@localhost>]

After i managed to finish a -current builds a few days ago, I thought I'd 
use sysinst's upgrade mode to update the system, for a change. Here are 
some findings:

 * Digging up the sysinst binary was a bit of a pain (obj/distrib/...),
   updating from a local directory was quite OK overall.
 * "postinstall check" fails - nothing critical, but no way to scroll back
   and see what actually fails, or to run "fix" or so.
 * I ended up with a /METALOG - is that intended? Interesting enough, that
   file is not in any of the created set files.
 * I expected some old backups to be in /etc.OLD or so, seems that's in
   /.sysinst now
 * /stand didn't get new modules installed - apparently the "modules.tgz"
   flag only has one file:

        # tar ztf modules.tgz
        ./etc/mtree/set.modules
        #

   This is somewhat bad, given that a modular kernel with no modules
   installed will not boot.

 * Thinking the system is ok, I gave it a reboot, resulting in:

        root file system type: ffs
        sh: Can't open /etc/rc
        Enterh pathname of shell or RETURN for /bin/sh:

Now off to fix the mess...


 - Hubert