Revert "ONC: Add FTEnabled property to WiFi"

This reverts commit 34f59cac92e1074d2e79c1461a7c71e6b632a13c.

Reason for revert: Speculative revert: appears to be breaking the stock Chromium Mac builder for WebRTC: https://ci.chromium.org/buildbot/chromium.webrtc/Mac%20Builder/93792
FAILED: obj/extensions/common/api/libgenerated_api.a 

Original change's description:
> ONC: Add FTEnabled property to WiFi
> 
> Support FTEnabled property in ONC.
> 
> BUG=791202
> TEST=chromeos_unittests
> TEST=chrome.networkingPrivate.createNetwork with "FTEnabled":true
> enables the device to connect to an FT network. Setting
> "FTEnabled":false disables the device from connecting to an FT
> network.
> 
> Cq-Include-Trybots: master.tryserver.chromium.linux:closure_compilation
> Change-Id: I2470753fd139505704987e301b18983dc51c5c47
> Reviewed-on: https://chromium-review.googlesource.com/982275
> Reviewed-by: Steven Bennetts <stevenjb@chromium.org>
> Commit-Queue: Matthew Wang <matthewmwang@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#549366}

TBR=stevenjb@chromium.org,cernekee@chromium.org,kirtika@chromium.org,matthewmwang@chromium.org

Change-Id: Ie29fdeaabecf4344ded8e0c5f9f6de1a04d8962e
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 791202
Cq-Include-Trybots: master.tryserver.chromium.linux:closure_compilation
Reviewed-on: https://chromium-review.googlesource.com/1004794
Reviewed-by: Patrik Höglund <phoglund@chromium.org>
Commit-Queue: Patrik Höglund <phoglund@chromium.org>
Cr-Commit-Position: refs/heads/master@{#549462}
12 files changed