For reference extension builds, update book_path to reference the appropriate...

For reference extension builds, update book_path to reference the appropriate file location. am: 8dbd7b96
am: ce46b862

* commit 'ce46b862':
  For reference extension builds, update book_path to reference the appropriate file location.

Change-Id: Icc7e68ec871661b3d2824452a4c12b24f9a83aee