Member pages mix usage of user and member pk's

Ghost User
2017-10-12T12:04:45+02:00

The members on the [member page of cohort 2017](https://thalia.nu/members/?filter=2017) are not linked to the right profiles.

### Current behaviour
When clicking on a member from cohort 2017, get redirected to a different member.

### Expected behaviour
When clicking on a member, get redirected to their member page.

### Steps to reproduce

1. Go to the [member page of cohort 2017](https://thalia.nu/members/?filter=2017).
2. Click on `Aniek den Teuling` with _member_ id `1559`.
3. Observe that you are redirected to `Romy Stähli` with _user_ id `1559`.