Add support for aggregate config.
Merge pull request #221 from icebourg/master

Add support for aggregate config.
make repo_urls adjustable via attributes
use double quotes to append pubkey.gpg
Prefer string interpolation instead of string concatenation
Merge pull request #223 from onehealth-cookbooks/GH-222

make repo_urls adjustable via attributes
[missing_ok] catch HTTPServerException & InvalidDataBagPath in data_bag_item()
Merge pull request #227 from portertech/missing_ok

Catch HTTPServerException & InvalidDataBagPath in data_bag_item()       - Fixes issues/225 & issues/224