update hooks: force upgrade of dev-install

In order to upgrade portage, we need to update dev-install to a version
that doesn't conflict with the new portage.

TEST=`./update_chroot` updated all boards to the latest dev-install

Change-Id: I60410b3d875b2b26fe895305f8b98b20578eb2a6
Reviewed-on: https://gerrit.chromium.org/gerrit/43058
Reviewed-by: David James <davidjames@chromium.org>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
1 file changed