pylint: Fix several warnings
Fixes Pylint warnings:
- R1729(use-a-generator)
- R1710(inconsistent-return-statements)
- R1727(condition-evals-to-constant)
Fixes: https://pagure.io/freeipa/issue/8772
Signed-off-by: Stanislav Levin <slev@altlinux.org>
Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>