message: Fix descriptor_tests not checking ToString output of public descriptors
diff: @@ -62,7 +62,7 @@ void Check(const std::string& prv, const std::string& pub, int flags, const std:
  // Check that both versions serialize back to the public version.
  std::string pub1 = parse_priv->ToString();
  - std::string pub2 = parse_priv->ToString();
  + std::string pub2 = parse_pub->ToString();
  BOOST_CHECK_EQUAL(pub, pub1);
  BOOST_CHECK_EQUAL(pub, pub2);
  