clean up unused nats code

Signed-off-by: Akihiro Suda <suda.akihiro@lab.ntt.co.jp>

vendor/github.com/nightlyone/lockfile/README.md

@@ -0,0 +1,52 @@
+lockfile
+=========
+Handle locking via pid files.
+
+[![Build Status Unix][1]][2]
+[![Build status Windows][3]][4]
+
+[1]: https://secure.travis-ci.org/nightlyone/lockfile.png
+[2]: https://travis-ci.org/nightlyone/lockfile
+[3]: https://ci.appveyor.com/api/projects/status/7mojkmauj81uvp8u/branch/master?svg=true
+[4]: https://ci.appveyor.com/project/nightlyone/lockfile/branch/master
+
+
+
+install
+-------
+Install [Go 1][5], either [from source][6] or [with a prepackaged binary][7].
+For Windows suport, Go 1.4 or newer is required.
+
+Then run
+
+	go get github.com/nightlyone/lockfile
+
+[5]: http://golang.org
+[6]: http://golang.org/doc/install/source
+[7]: http://golang.org/doc/install
+
+LICENSE
+-------
+BSD
+
+documentation
+-------------
+[package documentation at godoc.org](http://godoc.org/github.com/nightlyone/lockfile)
+
+install
+-------------------
+	go get github.com/nightlyone/lockfile
+
+
+contributing
+============
+
+Contributions are welcome. Please open an issue or send me a pull request for a dedicated branch.
+Make sure the git commit hooks show it works.
+
+git commit hooks
+-----------------------
+enable commit hooks via
+
+        cd .git ; rm -rf hooks; ln -s ../git-hooks hooks ; cd ..
+