lnwatcher: use is_mine(addr) instead of (addr in get_addresses())

small performance gain

electrum/lnwatcher.py

@@ -217,7 +217,7 @@ class LNWatcher(AddressSynchronizer):
             self.channel_status[outpoint] = 'closed (deep)'
         tx = self.db.get_transaction(txid)
         for i, o in enumerate(tx.outputs()):
-            if o.address not in self.get_addresses():
+            if not self.is_mine(o.address):
                 self.add_address(o.address)
             elif n < 2:
                 r = self.inspect_tx_candidate(txid+':%d'%i, n+1)