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.

BUG=chromium:984182
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>
diff --git a/update_chroot b/update_chroot
index 39cb16e..dc47dce 100755
--- a/update_chroot
+++ b/update_chroot
@@ -86,9 +86,7 @@
 
 # Make sure depot_tools is bootstrapped, so that it can build chromeos-chrome.
 info "Bootstrapping depot_tools"
-# depot_tools doesn't support Python 3 at all.
-# TODO(crbug.com/984182): Drop EPYTHON setting if they ever finish.
-EPYTHON="python2" ensure_bootstrap
+ensure_bootstrap
 
 # Perform an update of all the sdk packages in the chroot.
 EMERGE_CMD="${CHROMITE_BIN}/parallel_emerge"