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- Makes NTLMv2 the default version.
- This implicitly disables NTLMv1.
- Leaving the flag available for the first release with the
  default changed.
- Subsequent release will remove the flag but leave a policy.

BUG=chromium:22532

Change-Id: Ibb2778806b2a19b70abbc5300d20e06327077fb8
Reviewed-on: https://chromium-review.googlesource.com/885509
Commit-Queue: Zentaro Kavanagh <zentaro@chromium.org>
Reviewed-by: Asanka Herath <asanka@chromium.org>
Reviewed-by: Ryan Sleevi <rsleevi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#532552}