Upload a file to temporary path and move it to correct path

There may be a case that specinfra upload files by non-root user.
This causes a permission problem.

So upload file to temporary path and move it to correct path.
When moving it, specinfra use sudo. So no permission problems.
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Merge pull request #192 from serverspec/upload-file-to-temporary-path-and-move-it

Upload a file to temporary path and move it to correct path