Code review comment for lp:~lifeless/bzr/bug-514090

A small note, there's been a long-standing bug in both mod_python and mod_wsgi where threading.local() objects only last for a single request:
<http://code.google.com/p/modwsgi/issues/detail?id=120>

I presume however this doesn't affect launchpad, and would at worst just make the cache useless.