JSON representation for a query with an empty X-NXfetch.document header should not include all external entities

The X-NXfetch.document header can be used to load additional parts of an object whose entity-type is document.

But an empty value should not return all possible external objects.

For instance the following query returns all user entities of dublincore:

curl -u Administrator -X GET 'http://demo.nuxeo.com/nuxeo/api/v1/query?query=SELECT%20%2A%20FROM%20Document&pageSize=10&maxResults=100&currentPageIndex=0&sortBy=&sortOrder='  -H 'X-NXproperties: *' -H 'X-NXfetch.document;'  -vv