Merge pull request #256 from autocrypt/timestamp-cleanup

s/gossip_key_timestamp/gossip_timestamp/ for consistency

doc/level1.rst

@@ -526,7 +526,7 @@ Preliminary Recommendation
 __________________________
 
 If either ``public_key`` is ``null``, or ``autocrypt_timestamp`` is
-more than 35 days older than ``gossip_key_timestamp``, set
+more than 35 days older than ``gossip_timestamp``, set
 ``target-keys[to-addr]`` to ``gossip_key`` and set
 ``preliminary-recommendation`` to ``discourage`` and skip to the
 :ref:`final-recommendation-phase`.