new hobbit install, small mod request

[Tracy Di Marco White]

I installed hobbit over the weekend on what was to be my new BB servers,
and I'm impressed, and things have gone pretty well converting from BB
to hobbit.  I'm very impressed by the trending, and the difficulty I
was having integrating larrd into BB was the impetus for my changing.
I have one BBDISPLAY & one BBNET.

I use NetBSD, and I would like to see a small change that shouldn't
be problematic.

I'd like the df test in the NetBSD client to include 'null' as a
filesystem to exclude, so basically just changing:
df -P -tnonfs,kernfs,procfs,cd9660
to
df -P -tnonfs,kernfs,procfs,cd9660,null

On NetBSD, null mounts are loopback, so they're a duplication of
an already existing filesystem.

Tracy J. Di Marco White
Information Technology Services
Iowa State University