Determine which file an error occurs in

cherry-pick enhancement from PR #516

git cherry-pick aaecdfd71fc027f125662eb0ec1de96e344b9615

Conflicts:
	supervisor/options.py
	supervisor/tests/test_options.py
Merge pull request #529 from msabramo/cherry-pick_pr_516_to_3.2-branch

Determine which file an error occurs in