I think I've always been on record as disliking the nuking approach. I do realize that `flushdb` only applies to a single db, but it's too easy to gloss over the config / forget to, and I think a small inconvenience is worth the protection of not deleting data just by virtue of running tests.

@Myron -- why don't you go ahead and implement your suggestion to prevent the automatic deletion, perhaps with a helpful message indicating what you should manually flush the db.