Merge "adbconnection: silence logspam." am: ff08a51a

  int rc = connect(ctx->control_socket_.get(), reinterpret_cast<sockaddr*>(&addr), addr_len);

  if (rc != 0) {

    if (errno == ECONNREFUSED) {

      // On userdebug devices, every Java process is debuggable, so if adbd is explicitly turned

      // off, this would spew enormous amounts of red-herring errors.

      LOG(DEBUG) << "failed to connect to jdwp control socket, adbd not running?";

    } else {

      PLOG(ERROR) << "failed to connect to jdwp control socket";

    }

    return nullptr;

  }