libarchive: add hash for license file

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
(cherry picked from commit a3f5bf52b96827a78ae1cb5dd6b92abf25c76c5d)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/libarchive/libarchive.hash

@@ -1,2 +1,3 @@
 # Locally computed:
 sha256  ed2dbd6954792b2c054ccf8ec4b330a54b85904a80cef477a1c74643ddafa0ce  libarchive-3.3.2.tar.gz
+sha256  ae6f35cc1979beb316e4d6431fc34c6fc59f0dd126b425c8552bb41c86e4825d  COPYING