Nothing has changed as far as Passbook is concerned, and my machine is perfectly happy using the only two `.pem` files generated with `node-passbook prepare-keys`.

Either something changed with OpenSSL (for the record I'm using 0.9.8), or there's a different way to generate keys that require three of them, in which case `node-passbook prepare-keys` has to be fixed first.

We can't just merge this change and break node-passbook for everyone that's successfully using it with two keys, without offering them a way to generate the three necessary files.