adjusted PortalRouteProvider to match new RequestAnalyzer

Changes necessary due to https://github.com/sulu-cmf/sulu/pull/97

__Tasks:__

- [x] test coverage
- [x] gather feedback for my changes
- [ ] submit changes to the documentation

__Informations:__

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| Tests pass?   | yes
| Fixed tickets | none
| Doc           | none