Update django-celery version requirement from 3.0.17 to 3.0.21

This was needed, because version 3.0.17 couldn't satisfy its version
requirement for pytz anymore. And this in turn caused "pip install -r
pip-frozen" to fail.
Update distribute module dependency to version 0.7.3
Add tracing setup function that returns missing bits
Fix bug with project retrieval for tracing setup

The project object wasn't actually retrieved.