[22.01] Fix maintenance script bug

[jdavcs]

Fixes #14972, #15221

Bug was a result of the move from classical (imperative) mapping to declarative mapping.

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:

1. prior to change: bash scripts/maintenance.sh, observe errors as described in linked issues
2. apply change, run same command, observe no errors

License

• I agree to license these and all my past contributions to the core galaxy codebase under the MIT license.

[jdavcs]

any test failures are unrelated