Can you change this to:
```python
self.conn.cursor().execute("""
    TRUNCATE
        processors,
        server_status,
        report_partition_info,
        server_status,
        release_channels,
        reports
    CASCADE
""")
```

That's what we do in most other places.
Like this https://github.com/mozilla/socorro/blob/master/socorro/unittest/cron/jobs/test_suspicious_crashes.py#L79