Since @memoized now uses weakref to delete old cache entries, and no
longer keeps the object passed as parameters alive indefinitely, we
no longer need to treat the Request objects specially. In fact, if
we stop doing it, it should improve memory use, because now all
request-specific caches will be removed as soon as the request
object dies.
I also removed the memoized_with_argconv function, and replaced it
with an explicit function for converting teh parameters in the one
place where it was used.
Change-Id: I710b96a170e429c6ffdf22ad3e552ee6e1c6b7e3
3acb28270a