Netflix/Priam — pull request #80 by jasobrown (2012-10-04 21:45:51+00:00)
Title: Modify ICredential and add IAMCredential

Doing this as I realized there's a data race between calling the two existing
methods sequentially (as the cred provider could have updates keys between the two calls).
Added IAMCredential to use the Amazon IAM key fetcher thingamabob.