zstd_stream_wrapper unintialized 'ret' member

[yglushki]

In case of decompression 'ret' member is unitialized in constructor - that causes sporadic failures.
In my case 'ret' gets value of 0xffffffffffffffff - generic error and constructor fails.

{
    if (this->isInput) {
        // Case of decompression - this->ret is not set.
        this->dctx = ZSTD_createDCtx();
        if (this->dctx == NULL) throw zstdException("ZSTD_createDCtx() failed!");
    } else {
        this->cctx = ZSTD_createCCtx();
        if (this->cctx == NULL) throw zstdException("ZSTD_createCCtx() failed!");
        this->ret = ZSTD_CCtx_setParameter(cctx, ZSTD_c_compressionLevel, level);
    }
    if (ZSTD_isError(this->ret)) throw zstdException(this->ret);

}