Remove smart content filtered query build

__Tasks:__

- [x] test coverage
- [ ] gather feedback for my changes

__Informations:__

| Q             | A
| ------------- | ---
| Tests pass?   | yey
| Fixed tickets | https://github.com/sulu-cmf/sulu-standard/issues/278
| BC Breaks     | none
| Doc           | none
@wachterjohannes This line is causing an error, when the `dataSource` is `null`. If i refactor it to only execute that if the `dataSource` ist not null, and pass null to the `getParentNode`-function, if there is no node, another assert is failing.