Reorganize license files

The new layout better follows GNU recommendations and allows
licensee (and thus GitHub) to properly recognize the LGPL.

Change-Id: Ie4671f8a539ce5e4d7ea7fe644b9122716750728
diff --git a/docs/index.rst b/docs/index.rst
index 9886f33..7a0631b 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -23,4 +23,5 @@
 -------
 
 NAC is an open source project licensed under the LGPL version 3. For more information about
-the license, refer to `COPYING.md <https://github.com/named-data/name-based-access-control/blob/new/COPYING.md>`__.
+the license, refer to `COPYING.md <https://github.com/named-data/name-based-access-control/blob/new/COPYING.md>`__
+and `COPYING.lesser <https://github.com/named-data/name-based-access-control/blob/new/COPYING.lesser>`__.