[tests] Set -deprecatedrpc=accounts in tests

Future commits will deprecate the accounts RPC methods, arguments and
return objects. Set the -deprecatedrpc=accounts switch now so tests
don't break in intermediate commits.

test/functional/wallet_listsinceblock.py

@@ -11,6 +11,7 @@ class ListSinceBlockTest (BitcoinTestFramework):
     def set_test_params(self):
         self.num_nodes = 4
         self.setup_clean_chain = True
+        self.extra_args = [['-deprecatedrpc=accounts']] * 4
 
     def run_test(self):
         self.nodes[2].generate(101)