Copyright for vlock source package in Xenial

This is the Debian GNU/Linux's prepackaged version of the VC locking
command vlock(1).

It was put together from sources obtained from:
  ftp://tsx-11.mit.edu/pub/linux/sources/usr.bin/vlock-1.2.tar.gz
And later updated with sources obtained from:
  ftp://tsx-11.mit.edu/pub/linux/sources/usr.bin/vlock-1.3.tar.gz

Since 2.0 sources are obtained from:

http://cthulhu.c3d2.de/~toidinamai/vlock/archive/

Copyrights
----------
Copyright (C) 1994-1998 Michael K. Johnson 
Copyright (C) 2007 Frank Benkstein 

Modifications for Debian:
  Copyright (C) 1996 Dominik Kubla 
  Copyright (C) 1997-1998 Juan Cespedes 
  Copyright (C) 1999 Zephaniah E. Hull 
  Copyright (C) 2005 Peter Palfrader 
  

License
-------
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation version 2 only.

This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

A copy of the GNU General Public License is available as
`/usr/share/common-licenses/GPL-2' in the Debian GNU/Linux distribution or
on the World Wide Web at `http://www.gnu.org/copyleft/gpl.html'. You can
also obtain it by writing to the Free Software Foundation, Inc.,
51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA