update_chroot: allow python3 usage in depot_tools

The general scripts should be OK for Python 3, and any Python 2 scripts
should be using `python2` shebangs.  Lets relax the forcing of Python 2
here so depot_tools can start their migration.

TEST=CQ passes

Change-Id: I880f8b215f0a96772abcf4e7bff5ff434c3b60b0
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosutils/+/2753140
Reviewed-by: Sergey Frolov <sfrolov@google.com>
Tested-by: Mike Frysinger <vapier@chromium.org>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
1 file changed