Fix #52, use CFE_FS_InitHeader() to initialize CFE header

[havencarlson]

Checklist (Please check before submitting)

• [X] I reviewed the Contributing Guide.
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Describe the contribution Fix #52

Testing performed Unit testing

Expected behavior changes no impact to behavior

System(s) tested on

• OS: Ubuntu 18.04

Contributor Info - All information REQUIRED for consideration of pull request Haven Carlson - NASA