updater: Check entire service spec when deciding whether to replace ongoing update

Currently, updater checks isServiceDirty to decide whether an existing
update should be restarted. This only checks the task spec and the
endpoint spec, so it will ignore changes to fields like UpdateConfig.
For example, it's not possible to change just the parallelism while an
update is already in progress. Fix this by comparing the whole spec.

Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>

Author: Aaron Lehmann

manager/orchestrator/updater.go

@@ -49,7 +49,7 @@ func (u *UpdateSupervisor) Update(ctx context.Context, cluster *api.Cluster, ser
 	id := service.ID
 
 	if update, ok := u.updates[id]; ok {
-		if !update.isServiceDirty(service) {
+		if reflect.DeepEqual(service.Spec, update.newService.Spec) {
 			// There's already an update working towards this goal.
 			return
 		}