fix(rax-scripts): command line option "--output-path" not working

[Clarence-pan]

The "--output-path" option of "rax-scripts" was not working. I've found the reason, and figured out a
simple solution.

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1. Fork the repo and create your branch from master.
2. If you've added code that should be tested, add tests!
3. If you've changed APIs, update the documentation.
4. Ensure the test suite passes (npm test).
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[wssgcg1213]

这里可以这么做的原因是 cli 里面把参数映射到 env 里了, 这种有副作用的映射可能会导致一些不可预知的问题, 不过这是另一个话题了.

I would approve this change.