[tests] Don't subclass from object for Python 3

test/functional/test_framework/coverage.py

@@ -14,7 +14,7 @@ import os
 REFERENCE_FILENAME = 'rpc_interface.txt'
 
 
-class AuthServiceProxyWrapper(object):
+class AuthServiceProxyWrapper():
     """
     An object that wraps AuthServiceProxy to record specific RPC calls.