Data API button not shown (g.plugins empty)

On the resource page, the "Data API" button is never shown even if the datastore plugin is activated. That's because g.plugins seems to be empty.

````
  {% if 'datastore' in g.plugins %}
    <li>{% snippet 'package/snippets/data_api_button.html', resource=res, datastore_root_url=c.datastore_api %}</li>
  {% endif %}
````