Copy and Move constructors/assignments of ssl_options are not handling caPath_

[Thiesius]

Following snippet from my code is enough to reproduce the issue.

  mqtt::ssl_options opts;
  opts.set_enable_server_cert_auth(true);
  opts.set_ssl_version(MQTT_SSL_VERSION_TLS_1_2);
  // opts.set_enabled_cipher_suites() TODO: Do we want to restrict cipher list?
  opts.set_key_store(variant.certificate);
  opts.set_private_key(variant.key);
  opts.ca_path(variant.certificateAuthorityDir);
  opts.set_error_handler([](const std::string& errMsg) {
  //...
  });
  optsBuilder.ssl(std::move(opts));
  
  auto tok = client_.connect(opts);
  tok->wait();

This should by easy to fix.

Hack-fix - in case someone having the same issue can't wait until the member variable gets copied/moved correctly in next library release:

...
 optsBuilder.ssl(std::move(opts));
 mqtt::ssl_options& sslOpts = const_cast<mqtt::ssl_options&>(opts.get_ssl_options());
 sslOpts.ca_path(tlsSetup->certificateAuthorityDir);
 auto tok = client_.connect(opts);
...

[fpagliughi]

Yeah, that looks like a bug. Thanks for the report!