updater: Decrease default monitoring period
updater: Decrease default monitoring period

The updater monitors a tasks after they start to make sure they don't
fail immediately. The default time interval for this is 30s. However,
this is a bit long for synchronous updates to wait. Reduce it to 5s.
Users who would like a longer monitoring period should specify their own
value, or ideally use a health check in the service definition.

Signed-off-by: Aaron Lehmann <8ecfc6017a87905413dcd7d63696a2a4c351b604@docker.com>

diogomonica/swarmkit,deljuven/swarmkit,fate-grand-order/swarmkit,sungwonh/swarmkit,cheyang/swarmkit,jlhawn/swarmkit,RenaudWasTaken/swarmkit,dperny/swarmkit-1,cheyang/swarmkit,RenaudWasTaken/swarmkit,diogomonica/swarmkit,docker/swarmkit,AliyunContainerService/swarmkit,allencloud/swarmkit,fate-grand-order/swarmkit,AliyunContainerService/swarmkit,Noyan759/swarmkit,jlhawn/swarmkit,elifa/swarmkit,docker/swarmkit,allencloud/swarmkit,alyyousuf7/swarmkit,Noyan759/swarmkit,elifa/swarmkit,deljuven/swarmkit,alyyousuf7/swarmkit,dperny/swarmkit-1,sungwonh/swarmkit