MTP: check for replacing existing files via the database instead of the file system

        path += "/";

    path += (const char *)name;

    // file should not already exist

    if (access(path, R_OK) == 0)

        return MTP_RESPONSE_GENERAL_ERROR;

    // check space first

    if (mSendObjectFileSize > storage->getFreeSpace())

        return MTP_RESPONSE_STORAGE_FULL;