Fix failing OMP pipeline for 03-He-Hartree-Fock-test

Description

This MR is fixing an uninitialized variable inside an OMP region which caused the 03-He-Hartree-Fock.test to fail.

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Checklist

• I have checked that my code follows the Octopus coding standards
• I have added tests for all the new features added in this request.

Closes #383 (closed)