[fix] No longer silently fails on bad connection.

Also now sends the error object down the stack.

Having connect-redis listen to this prevents the exception from being thrown. However, since we might still want to pass the error don the stack, log what the error was anyways, just in case.


@visionmedia I'm guessing it would be better to throw an actual exception, but I'm not sure how to do that with a pre-existing Error object and listeners.