Merge upstart and EBS changes from https://github.com/maplebed/chef-mongodb/tree/parse_changes.

Remove the use of encrypted data bags from backup.rb and replace with the aws cookbook's new
databag_name and databag_entry stuff.

This requires the updates to the AWS cookbook.
Merge pull request #1 from kwarter-cookbooks/ebs

Merge upstart and EBS changes from Parse.