Handlebars helpers have different signature than used

The signature for all handlebar helpers is:

  function( args..., options );

Meaning there is a variable number of arguments and the final argument
is an options object.  Patch updates the l10n helper to appropriatly
take this into account.  Also updates the couple places that call l10n
directly to call it as it expects.

This resolves an inconsistency where the same function was being called two
different ways resulting in different results.

Bug: 71318
Change-Id: I972783d35056ac24b8a81bdc08a4cd99d36e0b76
(cherry picked from commit 05e678a067a95f590a7dacc6367694a69544d0e1)