What you are doing is setting up RAILS_ENV for your rails application. You can view the source here : https://github.com/aws/opsworks-cookbooks/blob/master/unicorn/definitions/unicorn_web_app.rb
this does not set the shell / ssh enviornment variable for you when you ssh login.
to do that manually :
sudo su deploy # change to deploy user
cd /srv/www/application_short_name/current # drop into the specific directory
RAILS_ENV=opsworks rails c
This will give you the appropriate rails env when you're running the commands.
You can automate this part / make it easier by creating a .bashrc file for your users with the following lines added :
export RAILS_ENV=opsworks