Remove the old NFS client and server from head,
which means that the NFSCLIENT and NFSSERVER
kernel options will no longer work. This commit
only removes the kernel components. Removal of
unused code in the user utilities will be done
later. This commit does not include an addition
to UPDATING, but that will be committed in a
few minutes.

Discussed on: freebsd-fs


git-svn-id: svn+ssh://svn.freebsd.org/base/head@276096 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f