tests/setupwizard: remove extra TSettings::destroy
tests/setupwizard: remove extra TSettings::destroy

This should only happen in cleanupTestCase(), unless you're doing weird
tests specificially on TSettings as in tests/core.

Tarsnap/tarsnap-gui,Tarsnap/tarsnap-gui,Tarsnap/tarsnap-gui,Tarsnap/tarsnap-gui,Tarsnap/tarsnap-gui