Remove cache directory from build tests
It seems that there is persist-ency that is introduced in docker container handling due to failures in the python docker sdk. This was found during build log analysis as part of https://gitlab.com/BuildStream/benchmarks/merge_requests/45 This patch makes sure that buildstream caches are cleared before taking measurements.
Changes proposed in this merge request:
- Delete buildstream cache directories prior to running build tests.
This merge request, when merged, will address issue/bug:
Failures in differential log parsing analysis.