Problem Definition

Currently, build working directories are structured based on the buildKey (e.g., PROJ-PLAN-JOB1).

Suggested Solution

Use the buildResultKey (buildKey + buildNumber) as the working directory.
Some pros: guarantees that all build jobs run in an unique location, allows previous build artifacts to remain (specially from failed builds), and doesn't incur the performance penalty of cleaning up the directory in every new build.