For reference extension builds, update book_path to reference the appropriate file location. am: 8dbd7b96cf am: ce46b86219
am: 1d2dbfe4f5

* commit '1d2dbfe4f5d929d5c671a1d73ec38d8246b1b17a':
  For reference extension builds, update book_path to reference the appropriate file location.

Change-Id: Id5ddec169d92b36f05a1d29b189b92f74396acb5