*: make GNU licensing statement forms more regular

This change retains "or later" state! No licensing _changes_ here,
only form is adjusted (article, space between "GPL" and "v2" and so on).

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

debianutils/Kbuild.src

@@ -2,7 +2,7 @@
 #
 # Copyright (C) 1999-2005 by Erik Andersen <andersen@codepoet.org>
 #
-# Licensed under the GPL v2, see the file LICENSE in this tarball.
+# Licensed under GPLv2, see file LICENSE in this source tree.
 
 lib-y:=
 

debianutils/mktemp.c

@@ -6,7 +6,7 @@
  * Copyright (C) 2000 by Daniel Jacobowitz
  * Written by Daniel Jacobowitz <dan@debian.org>
  *
- * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  */
 
 /* Coreutils 6.12 man page says:

debianutils/pipe_progress.c

@@ -4,7 +4,7 @@
  *
  * Copyright (C) 2003 by Rob Landley <rob@landley.net>, Joey Hess
  *
- * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  */
 #include "libbb.h"
 

debianutils/run_parts.c

@@ -12,7 +12,7 @@
  *   Copyright (C) 1996-1999 Guy Maor <maor@debian.org>
  *
  *
- * Licensed under GPL v2 or later, see file LICENSE in this tarball for details.
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  */
 
 /* This is my first attempt to write a program in C (well, this is my first

debianutils/start_stop_daemon.c

@@ -5,7 +5,7 @@
  * Written by Marek Michalkiewicz <marekm@i17linuxb.ists.pwr.wroc.pl>,
  * Adapted for busybox David Kimdon <dwhedon@gordian.com>
  *
- * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  */
 
 /*

debianutils/which.c

@@ -5,7 +5,7 @@
  * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
  * Copyright (C) 2006 Gabriel Somlo <somlo at cmu.edu>
  *
- * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  *
  * Based on which from debianutils
  */