libmhash: add hash for license file

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/libmhash/libmhash.hash

@@ -1,2 +1,3 @@
 # Locally computed:
 sha256  56521c52a9033779154432d0ae47ad7198914785265e1f570cee21ab248dfef0  mhash-0.9.9.9.tar.bz2
+sha256  d245807f90032872d1438d741ed21e2490e1175dc8aa3afa5ddb6c8e529b58e5  COPYING