Add chroot upgrade script to update masters for freon boards

BUG=chromium:476696
TEST=ran chroot upgrad hooks
CQ-DEPEND=CL:265741,CL:265750

Reviewed-on: https://chromium-review.googlesource.com/265736
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Reviewed-by: Michael Spang <spang@chromium.org>
Tested-by: Haixia Shi <hshi@chromium.org>
Trybot-Ready: Michael Spang <spang@chromium.org>
(cherry picked from commit b90465df235065d54b6ffaff9e0c80acfb38a020)

Change-Id: Icc069fb3579c96b462a1d062bc519790b4995b21
Reviewed-on: https://chromium-review.googlesource.com/266023
Reviewed-by: Michael Spang <spang@chromium.org>
Tested-by: Michael Spang <spang@chromium.org>
1 file changed