I can't see any users of this version via cs/, so drop it to speed up
the ensure_bootstrap phase.

Change-Id: Ib1e3ca75f1d091161c57a33f238c64973949a584
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/3246413
Auto-Submit: Mike Frysinger <vapier@chromium.org>
Reviewed-by: Josip Sokcevic <sokcevic@google.com>
Commit-Queue: Josip Sokcevic <sokcevic@google.com>