*: 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/libbb/get_line_from_file.c b/libbb/get_line_from_file.c
index cbfb45b..a0ed919 100644
--- a/libbb/get_line_from_file.c
+++ b/libbb/get_line_from_file.c
@@ -6,7 +6,7 @@
  * Copyright (C) 2004 Erik Andersen <andersen@codepoet.org>
  * Copyright (C) 2001 Matt Krai
  *
- * 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"