*: 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/networking/route.c b/networking/route.c
index a319962..c72e945 100644
--- a/networking/route.c
+++ b/networking/route.c
@@ -10,7 +10,7 @@
  *              Fred N. van Kempen, <waltje@uwalt.nl.mugnet.org>
  *              (derived from FvK's 'route.c     1.70    01/04/94')
  *
- * 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.
  *
  *
  * displayroute() code added by Vladimir N. Oleynik <dzo@simtreas.ru>