Load fundamental apps, before any possible customizing app may follow

ac7fb1b2 brought a regression that fundamental apps are not loaded anymore in some circumstances.

Examples:
- LDAP user logs in, but cannot use text editor
- LDAP user logs in first time, First Time Wizard does not show up
(both described in https://github.com/owncloud/core/issues/8963#issuecomment-46088834)

My fix is just to load the fundamental app types – authentication, then filesystem and logging –  before anything else (as it properly happens in other places, i guess it was just overseen).

@PVince81 @LukasReschke @DeepDiver1975 

Just saying that we *have* to populate `OC::$REQUESTEDAPP` - I think moving this to the router would be the easiest (surely not the cleanest) solution :-)