mange.py have to use USR2 signal if they want to upgrade the django
version instread of HUP. On the other hand, upgrading django version
with HUP is possible with gunicorn_django command.
blocking operation django example (we read a file already on the fs and
recreate another which blocked async schedulers).
While I'm here ease the code of eventlet worker. Just use the convenient
eventlet.serve function which already manage what we do and revert sopme
useless changes in body and header parsing.
