pull in 9vx

["Russ Cox" <rsc@swtch.com>]

If you give 9vx a full Plan 9 distribution, you can use
pull to update it just like any other distribution.
Early copies of 9vx had a /dist/replica/client/plan9.db
but it didn't match all the files I'd deleted to cut the
size of the archive down.  In 0.12 I deleted the plan9.db
too, so that pull wouldn't try to run.

If you want to run pull, you should start with a full tree.
I have posted one at http://pdos.csail.mit.edu/~rsc/plan9.tar.bz2
You should be able to run pull successfully if you use
that tree as your root.

You can also start with a stock Plan 9 CD, if you know how
to extract it into your local file system, but you will need
to populate /dist/replica/client appropriately and also
copy /dist/replica/network from a 9vx tree, since I haven't
gotten those changes back into the distribution yet.

Russ