Description of problem:

When running an analysis with the 'skip-static-report' option, the folder specified in the 'output' argument is not cleared.

This can result in a situation where, after conducting a regular analysis and then another one omitting the report, the report from the first analysis remains in place, while the logs and YAML files belong to the new analysis. This can be confusing for the user

Version-Release number of selected component (if applicable): upstream 

How reproducible: Always 

Steps to Reproduce:
1. Execute an analysis without providing the skip-static-report option
2. Execute an analysis providing the skip-static-report and ensure the output directory is the same one as the previous analysis

Actual results:

The output folder now has the static report from the first analysis and the output files from the second one

Expected results: 

Kantra should clear the directory (or provide an argument to do it) before placing any new files.