Code review comment for lp:~seif/zeitgeist/add_cache_for_get_events

I've seen discussions on memory usage in irc today (seif complaining about this cache using >30 MB writable memory), and I think I found a bug:

20:39 < thekorn> seiflotfy: I think I know what's making the cache size bigger
                 than max_size
20:39 < thekorn> seiflotfy: can you please remove old.next = None in line
                 125 of lrucache.py
20:40 < thekorn> and check writable memory again
20:41 < thekorn> if I get 4000 events with a cache size of 2000 I've 14MB
                 writable memory
20:41 < thekorn> which is far away from your 30MB