This reverts commit 331a276b.

Reason for revert: Looks like this is causing bots to fail on the waterfall

Example:
https://logs.chromium.org/v/?s=chromium%2Fbb%2Fchromium%2FWin%2F60913%2F%2B%2Frecipes%2Fsteps%2Fbot_update%2F0%2Fstdout

Original change's description:
> bot_update: make --output_json required in script invocation.
> 
> It's already set by recipe, so this should have 0 difference in prod.
> 
> R=​iannucci@chromium.org
> 
> Bug:
> Change-Id: I1e1129b9748d6647e45eb26892c8e892019fe088
> Reviewed-on: https://chromium-review.googlesource.com/769164
> Reviewed-by: Robbie Iannucci <iannucci@chromium.org>
> Commit-Queue: Andrii Shyshkalov <tandrii@chromium.org>

TBR=iannucci@chromium.org,tandrii@chromium.org

Change-Id: I65d7665e45dde539f6436ffe8932319e03f96f25
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/777619Reviewed-by: Andrii Shyshkalov <tandrii@chromium.org>
Commit-Queue: Andrii Shyshkalov <tandrii@chromium.org>