Fix #109, Uninitialized FileStats in FM_GetVolumeFreeSpace

[skliper]

Checklist (Please check before submitting)

• [x] I reviewed the Contributing Guide.
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Describe the contribution

• Fix #109

Testing performed CI

Expected behavior changes No static analysis uninitialized variable warnings

System(s) tested on CI

Additional context None

Third party code None

Contributor Info - All information REQUIRED for consideration of pull request Jacob Hageman - NASA/GSFC