Do not delete results directory if incremental-analysis is enabled
Do not delete results directory if incremental-analysis is enabled

Summary: Incremental analysis relies on analysis results in the results directory, so don't delete this directory if `--incremental-analysis` is used

Reviewed By: jvillard

Differential Revision: D16458113

fbshipit-source-id: bf7c63cb3

jvillard/infer,facebook/infer,jvillard/infer,facebook/infer,facebook/infer,facebook/infer,facebook/infer,facebook/infer,jvillard/infer,facebook/infer,jvillard/infer,jvillard/infer,jvillard/infer,jvillard/infer