fix deadlock: self.lock should be taken before self.transaction_lock

(self.lock is taken in self.get_tx.height)

electrum/wallet.py

@@ -867,7 +867,7 @@ class Abstract_Wallet(AddressSynchronizer, ABC):
         for txo in invoice.outputs:  # type: PartialTxOutput
             invoice_amounts[txo.scriptpubkey] += 1 if parse_max_spend(txo.value) else txo.value
         relevant_txs = []
-        with self.transaction_lock:
+        with self.lock, self.transaction_lock:
             for invoice_scriptpubkey, invoice_amt in invoice_amounts.items():
                 scripthash = bitcoin.script_to_scripthash(invoice_scriptpubkey.hex())
                 prevouts_and_values = self.db.get_prevouts_by_scripthash(scripthash)