Revert "autoupdate.py: Deprecate autoupdate.py"

This reverts commit 3de3e2bad7d6707a0548ead60ff4ab19f731ce7f.

Reason for revert: It turns out moblab still has this use case and there
are external users use it too. so I guess we have to just suck it up and
put this back.

Original change's description:
> autoupdate.py: Deprecate autoupdate.py
>
> This mechanism is not used in the lab anymore and has been replaced by
> gs_cache/nebraska_wrapper.py in crrev.com/c/2258234.
>
> BUG=chromium:1078188
> TEST=./devserver_integration_test.py
>
> Change-Id: Ifa007df983aab49c808360df6ba0b62b7031221c
> Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/dev-util/+/2486466
> Tested-by: Amin Hassani <ahassani@chromium.org>
> Commit-Queue: Amin Hassani <ahassani@chromium.org>
> Reviewed-by: Jae Hoon Kim <kimjae@chromium.org>

Bug: chromium:1078188, chromium:1149703
Change-Id: Ic9a1841419de5d4a7f2158e432cdaf3f79b273e9
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/dev-util/+/2546047
Tested-by: Amin Hassani <ahassani@chromium.org>
Commit-Queue: Amin Hassani <ahassani@chromium.org>
Reviewed-by: Amin Hassani <ahassani@chromium.org>
5 files changed