system: process all alerts before returning

Sometimes we can get suspended before we finish closing all our devices.

BUG=b:178128172
TEST=suspend and check order of suspend calls relative to dbus

Change-Id: I617598c241156d71dbdeecec4962ce8d9034a673
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/adhd/+/2671139
Commit-Queue: Ben Zhang <benzh@chromium.org>
Tested-by: Curtis Malainey <cujomalainey@chromium.org>
Auto-Submit: Curtis Malainey <cujomalainey@chromium.org>
Reviewed-by: Ben Zhang <benzh@chromium.org>
2 files changed