Store S3 keys in Config before calling db2fog
Store S3 keys in Config before calling db2fog

This ensures that Db2fog always picks up the latest value of the S3_*
env vars and not the one that was persisted last time. Now you can do
things like `S3_BUCKET=xxx bundle exec rake db2fog:backup` if you had
to.

openfoodfoundation/openfoodnetwork,lin-d-hop/openfoodnetwork,mkllnk/openfoodnetwork,Matt-Yorkley/openfoodnetwork,mkllnk/openfoodnetwork,lin-d-hop/openfoodnetwork,Matt-Yorkley/openfoodnetwork,mkllnk/openfoodnetwork,Matt-Yorkley/openfoodnetwork,mkllnk/openfoodnetwork,openfoodfoundation/openfoodnetwork,lin-d-hop/openfoodnetwork,lin-d-hop/openfoodnetwork,openfoodfoundation/openfoodnetwork,openfoodfoundation/openfoodnetwork,Matt-Yorkley/openfoodnetwork