revert refuel (neo #2444) neo-project/neo#2560 (#122)

Author: ixje

neo3/contracts/native/fungible.py

@@ -947,12 +947,3 @@ def on_persist(self, engine: contracts.ApplicationEngine) -> None:
         primary = pub_keys[engine.snapshot.persisting_block.primary_index]
         script_hash = to_script_hash(contracts.Contract.create_signature_redeemscript(primary))
         self.mint(engine, script_hash, vm.BigInteger(total_network_fee), False)
-
-    @register("refuel", contracts.CallFlags.STATES | contracts.CallFlags.ALLOW_NOTIFY, cpu_price=1 << 15)
-    def refuel(self, engine: contracts.ApplicationEngine, account: types.UInt160, amount: int):
-        if amount < 0:
-            raise ValueError("Cannot refuel with negative amount")
-        if not engine.checkwitness(account):
-            raise ValueError("[refuel] check witness failed")
-        self.burn(engine, account, vm.BigInteger(amount))
-        engine.refuel(amount)