populate used_addresses list in recoversync

Prior to this commit, the list of used addresses,
which is required to check for address reuse, is populated
on startup in fast sync, and updated as new transactions
arrive; but if --recoversync is chosen, this list was not
originally getting populated. This commit corrects that bug.

jmclient/jmclient/wallet_service.py

@@ -693,13 +693,14 @@ class WalletService(Service):
                     burner_txes.append((pubkeyhash, gettx))
 
             self.sync_burner_outputs(burner_txes)
-            used_addresses_gen = (tx["address"] for tx in tx_receive)
+            used_addresses_gen = set(tx["address"] for tx in tx_receive)
         else:
             #not fidelity bond wallet, significantly faster sync
-            used_addresses_gen = (tx['address']
+            used_addresses_gen = set(tx['address']
                                   for tx in self.bci._yield_transactions(wallet_name)
                                   if tx['category'] == 'receive')
-
+        # needed for address-reuse check:
+        self.used_addresses = used_addresses_gen
         used_indices = self.get_used_indices(used_addresses_gen)
         jlog.debug("got used indices: {}".format(used_indices))
         gap_limit_used = not self.check_gap_indices(used_indices)