Comment 9 for bug 811447

OK, this bug is a bit of "death by a thousand paper cuts," but looking at the OOPS, it looks like we can cut out a lot of fat with some small changes.

- about 4093 milliseconds can be removed from https://lp-oops.canonical.com/oops.py/?oopsid=2023D24 by cacheing the decision of whether a person is in a bug's administrated teams (the most repeated query in the OOPS analysis) in personsubscriptioninfo.py.

- The longest single query (1269 ms) comes from listifying bug.getSubscribersForPerson(self.user). I'm not sure how to improve that query for this case, but I can look at it.

- The next longest query (1215 ms) comes from getting all the subscriptions in a single big query. This is already optimized from getting the subscriptions singly. As before, I can look at this.

For https://lp-oops.canonical.com/oops.py/?oopsid=2064O33 (from comment 8), the first change will save 3632 ms.

I think I'll stop analyzing and start making this fix (the one in personsubscriptioninfo.py). We can find more optimizations, but this one is such an easy and big win that I should just do it.