MFC: r223747

MFC: r223747
Modify the new NFSv4 client so that it appends a file handle
to the lock_owner4 string that goes on the wire. Also, add
code to do a ReleaseLockOwner Op on the lock_owner4 string
before a Close. Apparently not all NFSv4 servers handle multiple
instances of the same lock_owner4 string, at least not in a
compatible way. This patch avoids having multiple instances,
except for one unusual case, which will be fixed by a future commit.
Found at the recent NFSv4 interoperability Bakeathon.

git-svn-id: svn://svn.freebsd.org/base/stable/8@224149 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f