special.js: Use then() instead of manually wrapping Deferred

* No need for the 'new' operator in $.Deferred. It's not an
  instantiable constructor with prototype but an object factory.
  Unnecessary overhead and didn't match code used elsewhere.

* Simplifies data processing to receiving data and returning
  the transformed value. No need to invoke a shared interface like
  d.resolve or d.reject.

Follows-up 76b57a8, 6ff803c.

Change-Id: Ie1887c9d8b31c19fef24acbc1cc4be1194930217