Fix the "ret_value" problem created by a little too much linting.

Add this to your merge proposal:
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lp:~raoul-snyman/openlp/fix-retvalue (revision 2684)
[SUCCESS] https://ci.openlp.io/job/Branch-01-Pull/1666/
[SUCCESS] https://ci.openlp.io/job/Branch-02-Functional-Tests/1577/
[SUCCESS] https://ci.openlp.io/job/Branch-03-Interface-Tests/1515/
[SUCCESS] https://ci.openlp.io/job/Branch-04a-Windows_Functional_Tests/1280/
[SUCCESS] https://ci.openlp.io/job/Branch-0...