Allow deleting parameterless memoized caches

I have some functions that take no parameters that I'm caching using memoize().  They typically expire in 48 hours (fairly static), but if I update something, I want to manually delete and refresh the cache.  If you do the follow it failed before:

cache.delete_memoized(myFunc)
myFunc()

This is because the version_key had no timeout set, so it was expiring in 240 seconds with my Redis backend (perhaps that is the default I had set somewhere).  Regardless, it wasn't using the timeout parameter that the version_data was using thus making the cache effectively expire far before I wanted it to.