Tech - Doctors: CleanUp old builds' folders [#52116853]

Pivotal tracker story [#52116853](http://www.pivotaltracker.com/story/show/52116853) in project *Tech - Doctors*:

> Currently we keep 2 last builds for given project.
> 
> Lets change this logic to keep:
> - Two latest builds' directories for given project (across all slave machines)
> - But for not longer than a day