added global ignore flag for bytecode cleanup

[MattPark]

Resolves #1867

Description

This keeps git from looking for global ignore directory especially when it doesn't exist (which throws a scary looking warning)

Fixes #1867

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Made the change locally, successfully postprocessed without the error

Test Configuration:

Checklist:

• I have based this change on the nightly branch
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes