Fix test failure due to RBFR

Author: petertodd

test/functional/feature_rbf.py

@@ -657,8 +657,10 @@ def test_incremental_relay_feerates(self):
                 assert_greater_than(replacement_required_fee, replacee_tx['fee'])
 
             # 1 satoshi shy of the required fee
-            failed_replacement_tx = self.wallet.create_self_transfer(utxo_to_spend=confirmed_utxo, fee=replacement_required_fee - Decimal("0.00000001"))
-            assert_raises_rpc_error(-26, "insufficient fee", node.sendrawtransaction, failed_replacement_tx['hex'])
+            _failed_replacement_tx = self.wallet.create_self_transfer(utxo_to_spend=confirmed_utxo, fee=replacement_required_fee - Decimal("0.00000001"))
+
+            # DISABLED: replace-by-fee-rate accepts this class of tx
+            # assert_raises_rpc_error(-26, "insufficient fee", node.sendrawtransaction, failed_replacement_tx['hex'])
 
             replacement_tx = self.wallet.create_self_transfer(utxo_to_spend=confirmed_utxo, fee=replacement_required_fee)
             node.sendrawtransaction(replacement_tx['hex'])