Core: Path generated in the Swagger doc don't take into account `app_dev.php`

[dunglas]

Steps to reproduce:

1. Install API Platform using Docker
2. Download http://localhost/app_dev.php/doc.json

The Swagger document should include app_dev.php paths, it doesn't.
So, when using Swagger UI in dev mode, requests are sent in prod mode.

cc @Simperfit

[Simperfit]

@dunglas I've checked this issue and I can't reproduce it (with last api-platform/api-platform)

here is my view with a dummy entity :

[dunglas]

I just checked with @Simperfit and we confirm this bug impact dev-master (but not the last beta).

This bug has probably been introduced in #666 (cc @Ener-Getick). Maybe should we call an exorcist.

[GuilhemN]

This should be fixed using basePath i guess, i'll try to do that tonight.