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: d381d302

* commit 'd381d302':
  For reference extension builds, update book_path to reference the appropriate file location.

Change-Id: I1fcf6f0a54b9cdc49bc2cf23ee40f02769349604