Simplify onSetup check for configuration
- No need for isset(), because these are created by default. If they were unset somehow, the run-time warning for that should not be hidden.
- No need to check DBname. Optional.
- Fix BagOStuff typehint.
Ref T180192.
Change-Id: Idd64e1811fbfb88302769a568369c58e66b5fa03