How do I flush the keypool? After the heartbleed vulnerability, I'm concerned that my private keys could have been compromised.  I want to send all my coins to a new address with a freshly generated key.

However, if I just ask the Bitcoin Core client to generate a new address, it will just select one from the existing keypool.  The keypool keys may also have been compromised, so I don't want to use them.  I want a key that is really brand new.

Short of asking Bitcoin to generate hundreds of new addresses to exhaust the keypool, is there a way to flush the keypool and start getting fresh addresses?

I understand this happens when you encrypt a wallet, but I prefer not to do that.  (Anyway, if my wallet was already encrypted, that wouldn't be an option.)
If you call getnewaddress 100 times (via RPC for bitcoind, in the debug console for Bitcoin-Qt), the key pool is flushed.

After that, you can request one more new address and send all your funds there.