Propagate my dpkg-buildpackage copyright notice to other locations

Sync the copyright notice from usage() with the man page
and add 2007 to my debian/copyright entry.

debian/copyright

@@ -1,6 +1,6 @@
 This is Debian's package maintenance system.
 
-Copyright © 2006 Frank Lichtenheld <djpig@debian.org>
+Copyright © 2006-2007 Frank Lichtenheld <djpig@debian.org>
 Copyright © 2004-2005 Scott James Remnant <scott@netsplit.com>
 Copyright © 2004-2005 Canonical Ltd.
 Copyright © 1999-2002 Wichert Akkerman <wakkerma@debian.org>

man/dpkg-buildpackage.1

@@ -203,6 +203,8 @@ and initial arguments for
 Copyright (C) 1995-1996 Ian Jackson
 .br
 Copyright (C) 2000 Wichert Akkerman
+.br
+Copyright (C) 2007 Frank Lichtenheld
 .sp
 This is free software; see the GNU General Public Licence version 2 or later
 for copying conditions. There is NO WARRANTY.