tests: Use explicit imports

test/functional/wallet_fallbackfee.py

@@ -4,7 +4,7 @@
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 """Test wallet replace-by-fee capabilities in conjunction with the fallbackfee."""
 from test_framework.test_framework import BitcoinTestFramework
-from test_framework.util import *
+from test_framework.util import assert_raises_rpc_error
 
 class WalletRBFTest(BitcoinTestFramework):
     def set_test_params(self):