Revert of "Log force-alt-protocols command line flag usage".

Revert of "Log force-alt-protocols command line flag usage".

Revert of "Log force-alt-protocols command line flag usage" (patchset #2 id:20001 of https://codereview.chromium.org/879863004/).  Created manually by git revert ; git cl upload.

Reason for revert:
Reverting bogus CL.  base::RecordAction cannot be called on the IO thread.  This
CL actually causes debug build Chromium to crash upon startup if invoked with
the --use-spdy=force-alt-protocols command line flag.

Nothing else in io_thread.cc seems to be using "base/metrics/user_metrics.h", so
it seems to be safe to remove.

Original issue's description:
> Log force-alt-protocols command line flag usage.
>
> BUG=452514
>
> Committed: https://crrev.com/493bc568527caeab93a173e4feea85c0c86c439e
> Cr-Commit-Position: refs/heads/master@{#313566}

TBR=rch@chromium.org,asvitkine@chromium.org
BUG=452514

Review URL: https://codereview.chromium.org/1023483002

Cr-Commit-Position: refs/heads/master@{#321343}