Add chroot upgrade script to update masters for falco, wolf, leon

BUG=chromium:454515
TEST=ran chroot upgrade hooks
CQ-DEPEND=CL:245592

Change-Id: I63847b56316cb6d0f2ce82ae7d7034f0cf1f2b57
Reviewed-on: https://chromium-review.googlesource.com/245593
Reviewed-by: Haixia Shi <hshi@chromium.org>
Tested-by: Michael Spang <spang@chromium.org>
Reviewed-by: Michael Spang <spang@chromium.org>
Commit-Queue: Michael Spang <spang@chromium.org>
Trybot-Ready: Michael Spang <spang@chromium.org>
(cherry picked from commit 24cfc7952e6375f0c8dd278a20c3a67fc5c41546)
Reviewed-on: https://chromium-review.googlesource.com/255924
1 file changed