> curl -X DELETE --header 'etag: "13865833"' \
>                --dump - http://localhost:8529/collection/9496015/13658604
HTTP/1.1 409 Conflict
content-type: application/json
connection: Keep-Alive
server: triagens GmbH High-Performance HTTP Server

{ "error" : true,
  "message" : "document /collection/9496015/13658604 has been altered", 
  "code" : 409 }