*: 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/udhcp/packet.c b/networking/udhcp/packet.c
index 4badc9c..d8f9c5d 100644
--- a/networking/udhcp/packet.c
+++ b/networking/udhcp/packet.c
@@ -4,7 +4,7 @@
  *
  * Rewrite by Russ Dill <Russ.Dill@asu.edu> July 2001
  *
- * Licensed under GPLv2, see file LICENSE in this tarball for details.
+ * Licensed under GPLv2, see file LICENSE in this source tree.
  */
 #include <netinet/in.h>
 #if (defined(__GLIBC__) && __GLIBC__ >= 2 && __GLIBC_MINOR__ >= 1) || defined _NEWLIB_VERSION