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 am: 1d2dbfe4 am: 6598f780 am: 7423e937
am: a6d053c9

* commit 'a6d053c9':
  For reference extension builds, update book_path to reference the appropriate file location.

Change-Id: I2f754481c6c0b8a264698bc2069f1cf8096f198c