misc: multi-valued attributes and setinfo

it's a great moment when you come to understand something. understanding that you understand something at the wrong moment, however, is a point for debate. while i'm happy for the understanding, i wish it had come sooner. wrong moment by my logic is anytime you're knee-deep in a production change and "understand". :-] understanding how setinfo works with multi-valued attributes is really pretty simple. i'll blame it on "inadequate testing". to pontificate on this tidbit, if you're adding multiple email addresses, say to proxyAddresses, you can't queue up the changes and write them with one setinfo command. instead, you have to write one, commit, append another, commit, etc.