[22.01] fix lint context fail function

[bernt-matthias]

error introduced here #13186

found this while working on galaxyproject/planemo#1264

How to test the changes?

(Select all options that apply)

• I've included appropriate automated tests.
• This is a refactoring of components with existing test coverage.
• Instructions for manual testing are as follows:

The test that currently fails in the linked PR runs with this change:

planemo workflow_lint --fail_level error PLANEMODIR/tests/data/wf_repos/from_format2/0_basic_format2

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