Fix certificate file/dir on windows

[isuruf]

Checklist

• Used a personal fork of the feedstock to propose changes
• Bumped the build number (if the version is unchanged)
• Reset the build number to 0 (if the version changed)
• Re-rendered with the latest conda-smithy (Use the phrase @conda-forge-admin, please rerender in a comment in this PR for automated rerendering)
• Ensured the license file is being packaged.

[conda-forge-webservices]

Hi! This is the friendly automated conda-forge-linting service.

I just wanted to let you know that I linted all conda-recipes in your PR (recipe) and found it was in an excellent condition.

[h-vetinari]

Fine by me. It would be nice if the Anaconda folks could let us know of security-relevant fixes that happen in https://github.com/AnacondaRecipes/openssl-feedstock, I'm happy to back-/forwardport these, but in this case I wasn't aware.
CC @chenghlee @JeanChristopheMorinPerso @ryanskeith

We also might want to consider synching the two feedstocks again a bit more (i.e. merge back Anaconda's master branch, or more specifically AnacondaRecipes#21).

[h-vetinari]

We probably also want to backport this to all the maintenance branches.

[isuruf]

Merge? (I'm not a maintainer here)