Update Windows build to use VULKAN_SDK rather than VK_SDK_PATH

Update Windows build to use VULKAN_SDK rather than VK_SDK_PATH

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2318633002

Committed: https://skia.googlesource.com/skia/+/b2be02bb39351ed97e789f7d3e97c7180f72560f

[bsalomon, 2016-09-06 14:46:03]

Description was changed from

==========
Update Windows build to use VULKAN_SDK rather than VK_SDK_PATH

BUG=skia:
==========

to

==========
Update Windows build to use VULKAN_SDK rather than VK_SDK_PATH

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2318633002
==========

[bsalomon, 2016-09-06 14:47:16]

bsalomon@google.com changed reviewers:
+ egdaniel@google.com, jvanverth@google.com

[egdaniel, 2016-09-06 14:54:09]

lgtm. Will work as long as no one is using a very old version of the windows sdk
which I doubt anyone trying to do Vulkan stuff would do currently.

[bsalomon, 2016-09-06 15:22:45]

The CQ bit was checked by bsalomon@google.com

[commit-bot: I haz the power, 2016-09-06 15:22:52]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-09-06 15:40:53]

Description was changed from

==========
Update Windows build to use VULKAN_SDK rather than VK_SDK_PATH

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2318633002
==========

to

==========
Update Windows build to use VULKAN_SDK rather than VK_SDK_PATH

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2318633002

Committed:
https://skia.googlesource.com/skia/+/b2be02bb39351ed97e789f7d3e97c7180f72560f
==========

[commit-bot: I haz the power, 2016-09-06 15:40:54]

Committed patchset #1 (id:1) as
https://skia.googlesource.com/skia/+/b2be02bb39351ed97e789f7d3e97c7180f72560f