Do not delete non-duplicates when deleting duplicates
Do not delete non-duplicates when deleting duplicates

This is a hot fix which filters the `duplicate_list`s for findings which
are not duplicates.

OWASP/django-DefectDojo,OWASP/django-DefectDojo,rackerlabs/django-DefectDojo,rackerlabs/django-DefectDojo,OWASP/django-DefectDojo,OWASP/django-DefectDojo,OWASP/django-DefectDojo,rackerlabs/django-DefectDojo,rackerlabs/django-DefectDojo