Improving log message

`DefaultEnvironment` loads `environment.properties` and `production.properties`(or any other environment).
If application has only `production.properties` than no `environment.properties` gonna be found and log message will say: `If you ask for any property, null will be returned`.
This log message is wrong, because `production.properties` were loaded and properties are not null.

I just improve the log message to do not say that null values will be returned, instead of it only file not found message will be logged.