For reference extension builds, update book_path to reference the appropriate file location. am: 8dbd7b96cf
am: ce46b86219

* commit 'ce46b86219b973a5f90d16e5e59073952ef01519':
  For reference extension builds, update book_path to reference the appropriate file location.

Change-Id: Icc7e68ec871661b3d2824452a4c12b24f9a83aee