django-tokyo-sessions may not be closing connections properly

[ericflo]

(copied over from the PyTyrant ticket tracker)

We're testing a Django app with django-tokyo-sessions. At a certain point
in our stress tests pytyrant starts throwing a 99 error. Sounds like low
level UNIX. We increased the amount of threads to 24 (on a beefy machine).
50 concurrent requests in our test suite. We also tried to use memory
storage. Started throwing the error around the 9000 request count mark at
around 200 completed requests per second.

Traceback:

http://dpaste.com/hold/46340/