[BUGFIX] removed scope dependency from product manager

__Tasks:__

- [x] test coverage
- [x] gather feedback for my changes

__Informations:__

| Q             | A
| ------------- | ---
| Tests pass?   | no => https://github.com/sulu-cmf/sulu/pull/270/files
| Fixed tickets | none
| BC Breaks     | none
| Doc           | none