Subscribe to events and monitor for new containers before the initial
listing of currently running containers.
This fixes a race where a new container could appear between the first
list call but before the client was subscribed to events, leading to a
container never appearing in the output of `docker stats`.
Signed-off-by: Arnaud Porterie <arnaud.porterie@docker.com>
Upstream-commit: 3041aa53efbbfddbc10a66027d973bd353e3b525
Component: engine
26d7a7de66