Sbt builder fix and refactor

* Fixed the issue with lost deprecation warnings. #1002148
* Refactored and removed useless indirection in the build reporter

The best would be to review the two commits separatetly. The first one fixes the issue, the last one is purely cleanup.

/cc @gkossakowski
I didn't find out much, so I will follow your suggestion in a separate commit, so it's easy to revert if it's not good.