*: 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>
diff --git a/debianutils/mktemp.c b/debianutils/mktemp.c
index 7ce9f10..86881f8 100644
--- a/debianutils/mktemp.c
+++ b/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: