[HOTFIX] Stabilize content settings tab

__Tasks:__

- [x] gather feedback for my changes

__Related:__

https://github.com/sulu-cmf/sulu/pull/201 , https://github.com/sulu-cmf/sulu-standard/pull/173 , https://github.com/sulu-cmf/SuluAdminBundle/pull/153

__Informations:__

| Q             | A
| ------------- | ---
| Tests pass?   | yes
| Fixed tickets | https://github.com/sulu-cmf/SuluContentBundle/issues/166 , https://github.com/sulu-cmf/sulu-standard/issues/170
| BC Breaks     | none
| Doc           | none