Use more permissive isRevisionAllowed on helper tools.

getUserLinks etcetera are (among others) called from within logs,
to generate i18n params in history msgs.

Because of that, we'll want it to check only the current revision
(because that's where we'll getModerationState() from), whereas
isAllowed() will also check the most recent revision.

Change-Id: Ia3b259581978dd8389abcae6dec5a2ff69e67686