firewalld: Monitor permission_broker lifetime.

If/when permission_broker exits, plug all firewall holes.

BUG=None
TEST=Manual: deploy to device, punch a hole.
TEST='restart permission_broker', holes are punched.

Change-Id: I3885b2338ad25f79c50a7f8c0aa4375e092ecceb
Reviewed-on: https://chromium-review.googlesource.com/253790
Reviewed-by: Jorge Lucangeli Obes <jorgelo@chromium.org>
Commit-Queue: Jorge Lucangeli Obes <jorgelo@chromium.org>
Trybot-Ready: Jorge Lucangeli Obes <jorgelo@chromium.org>
Tested-by: Jorge Lucangeli Obes <jorgelo@chromium.org>
4 files changed