Revert of win: Fix current toolchain path with old packaging

Revert of win: Fix current toolchain path with old packaging (patchset #1 id:1 of https://codereview.chromium.org/1159433006/)

Reason for revert:
Breaking chromium waterfall.

Original issue's description:
> win: Fix current toolchain path with old packaging
> 
> I broke boringssl's use of depot_tools toolchain as I changed the
> name of the sdk path key. This happened to work in Chrome because
> src/ has fallback behaviour.
> 
> Restore the 'win8sdk' name when unpacking a current/old-style
> toolchain package (i.e. what everyone is still using).
> 
> TBR=dpranke@chromium.org
> R=davidben@chromium.org
> 
> Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=295492

TBR=davidben@chromium.org,dpranke@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=295493

[scottmg, 2015-06-02 19:37:10]

Created Revert of win: Fix current toolchain path with old packaging

[commit-bot: I haz the power, 2015-06-02 19:37:31]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1167753003/1

[commit-bot: I haz the power, 2015-06-02 19:37:47]

Committed patchset #1 (id:1) as
http://src.chromium.org/viewvc/chrome?view=rev&revision=295493

[Dirk Pranke, 2015-06-02 19:39:02]

lgtm