Implicit conversion from int to boolean was generating a warning on
MSVS 2013.

Still useful to keep support around at least while build instructions
recommend using MSVS 2013.

Change-Id: I6975198f4bc6740a745454375f422d9c67ffaea5
Reviewed-on: https://chromium-review.googlesource.com/329070Reviewed-by: Olli Etuaho <oetuaho@nvidia.com>