MFC: r210455, r210456

MFC: r210455, r210456
Move sys/nfsclient/nfs_lock.c into sys/nfs and build it as a separate
module that can be used by both the regular and experimental nfs
clients. This fixes the problem reported by jh@ where /dev/nfslock
would be registered twice when both nfs clients were used.
I also defined the size of the lm_fh field to be the correct value,
as it should be the maximum size of an NFSv3 file handle.
Also fix the include path for nfs_lock.h for usr.sbin/rpc.lockd/kern.c.

git-svn-id: svn://svn.freebsd.org/base/stable/8@210985 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f