OutputPage: Don't set 'user' module state if filtered out
On pages where the 'user' module is filtered out (e.g.
on Special:Preferences) it would export state 'loading' (or state
'ready') eventhough the actual call to makeResourceLoader() later
in getBottomScripts() would be a no-op due to filtering.
This would cause either an indefinite state of "loading" or a
state "ready" that wasn't true.
This restores status quo as it was before
80e5b160 and
3e7a50d5f.
Test plan:
* Logged-in with non-empty user page common.js.
* View Special:Preferences.
* Verify in <head> source code, or via mw.loader.getState('user')
that it has state "registered" (the default initial state) and
not state "loading" or "ready".
Change-Id: I9b360d7e12703bddb80793aef47296fd63032c3d