message: Fix wrapped serial functional test
  The error message had changed
diff: @@ -91,7 +91,7 @@ class zPIVwrappedSerialsTest(PIVX_FakeStakeTest):
  tx = self.node.spendrawzerocoin(serial, randomness, DENOM_TO_USE, privkey)
  except JSONRPCException as e:
  exc_msg = str(e)
  - if exc_msg == "The new spend coin transaction did not verify (-4)":
  + if exc_msg == "CoinSpend: failed check (-4)":
  self.log.info("GOOD: Transaction did not verify")
  else:
  raise e
  