Fixed the duplicate slots view.
The script would not clear the screen upon recalculation also the list of duplicates would increase with every iteration because the variables weren't properly reset.
Patch by: Merio Ferraro, Lennard de Rijk
Reviewed by: to-be-reviewed
#!/usr/bin/env python
"""
Daily cleanup job.
Can be run as a cronjob to clean out old data from the database (only expired
sessions at the moment).
"""
from django.core import management
if __name__ == "__main__":
management.call_command('cleanup')