Issues with ENV-variables override #4257
Description
Also did some tests ...
- not working if DB value exists
- Mage::getStoreConfig() does not work
- store config with overriden values should not have set "use default"
- store config with overriden values should be locked (to make it impossible to override ENV var with config)
- test fail for live data (rewritten tests to use installed OM)
Originally posted by @sreichel in #3863 (comment)