kit: Log UnitBase initialization on a more appropriate level

[thebearon]

Change-Id: Id4dd61173271fcae5ea941680a39ee9889a3969c

• Target version: master

Checklist

• [X] Code is properly formatted
• [X] All commits have Change-Id
• [ ] I have run tests with make check
• [X] I have issued make run and manually verified that everything looks okay
• [X] Documentation (manuals or wiki) has been updated or is not required