Testers: NFSv3 support for pxeboot for nfs diskless root

[Rick Macklem]

I put 3 patches (you need to apply them all) here:
http://people.freebsd.org/~rmacklem/nfsdiskless-patches/

They convert lib/libstand/nfs.c and pxeboot to use NFSv3 instead
of NFSv2 (unless built with OLD_NFSV2 defined). Initial test
reports have been good. (one has it working ok and the other has
a problem in an area not related to the patches, it appears)

So, if others are interested in testing these, it would be
appreciated, rick