Of/oc 9637

Previously, it was assumed that every field in a chef_object record was present in the database.  By allowing elective implementation of flatten_record in the chef_object, chef_objects may now choose to hold fields not backed by postgres.  This allows more types of data to be carried in chef_object records.

Additionally, use the delete_object chef_object api in chef_db/chef_sql.

Lever chef_object:flatten from https://github.com/opscode/chef_objects/pull/58