*: 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/archival/libunarchive/get_header_tar.c b/archival/libunarchive/get_header_tar.c
index d5c9235..cf64872 100644
--- a/archival/libunarchive/get_header_tar.c
+++ b/archival/libunarchive/get_header_tar.c
@@ -1,14 +1,14 @@
 /* vi: set sw=4 ts=4: */
-/* 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.
  *
- *  FIXME:
+ * FIXME:
  *    In privileged mode if uname and gname map to a uid and gid then use the
  *    mapped value instead of the uid/gid values in tar header
  *
- *  References:
+ * References:
  *    GNU tar and star man pages,
  *    Opengroup's ustar interchange format,
- *	http://www.opengroup.org/onlinepubs/007904975/utilities/pax.html
+ *    http://www.opengroup.org/onlinepubs/007904975/utilities/pax.html
  */
 
 #include "libbb.h"