Update client.rb

[steelcowboy]

See #179. This should be data_bags per https://github.com/chef/chef/blob/61a11902ab814aad3625eb4da7e3345d63ee7c09/knife/lib/chef/knife/data_bag_from_file.rb#L64

To repro:

1. Set up taste-tester to use the bundle option
2. Set up a client with a runlist containing databags to work with the local bundle
3. Observe that you get a 404.
4. Set data_bag_path "#{taste_tester_dest}/databag" in the client config and observe it now works

To test this change:

1. Create this change locally: sed -i "s#'databag'#'data_bags'#" /path/to/taste_tester/lib/taste_tester/client.rb
2. Upload a new bundle. Remove the data_bag_path override
3. Observe Chef in local mode now works

[jaymzh]

post-factro approval.

As to the bug, bundle-mode was written for the internal CI stuff that leverages taste-tester for prod, and of course prod at FB doesn't use databags, so it's not surprising this happened. Thanks for fixing it Jim!