*: 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>

util-linux/mkfs_reiser.c

@@ -4,7 +4,7 @@
  *
  * Busybox'ed (2009) by Vladimir Dronnikov <dronnikov@gmail.com>
  *
- * Licensed under GPLv2, see file LICENSE in this tarball for details.
+ * Licensed under GPLv2, see file LICENSE in this source tree.
  */
 #include "libbb.h"
 #include <linux/fs.h>