init: Reboot if dbus-daemon dies.

Rather than leave the system in a broken state, reboot
automatically if dbus-daemon exits.

BUG=chromium:432980
TEST=manual: system reboots after "killall -SEGV
     dbus-daemon" but not during a normal user-initiated
     shutdown

Change-Id: I49646a884e24e726bc6858044ee6cd606fb3b089
Reviewed-on: https://chromium-review.googlesource.com/238268
Trybot-Ready: Daniel Erat <derat@chromium.org>
Tested-by: Daniel Erat <derat@chromium.org>
Reviewed-by: Richard Barnette <jrbarnette@chromium.org>
Commit-Queue: Daniel Erat <derat@chromium.org>
1 file changed