Fix config test
Fix config test

The test failed if you modified your local config, which is stupid. Stubbing out fs.existsSync means the environment_config module never looks at your local config because it believes it to not exist.

alphagov/spotlight,keithiopia/spotlight,keithiopia/spotlight,tijmenb/spotlight,tijmenb/spotlight,alphagov/spotlight,alphagov/spotlight,tijmenb/spotlight,keithiopia/spotlight