Add support for UpToDate filter, for internal use

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

daemon/cluster/filters.go

@@ -53,6 +53,10 @@ func newListTasksFilters(filter filters.Args, transformFunc func(filters.Args) e
 		"service":       true,
 		"node":          true,
 		"desired-state": true,
+		// UpToDate is not meant to be exposed to users. It's for
+		// internal use in checking create/update progress. Therefore,
+		// we prefix it with a '_'.
+		"_up-to-date": true,
 	}
 	if err := filter.Validate(accepted); err != nil {
 		return nil, err
@@ -68,6 +72,7 @@ func newListTasksFilters(filter filters.Args, transformFunc func(filters.Args) e
 		Labels:       runconfigopts.ConvertKVStringsToMap(filter.Get("label")),
 		ServiceIDs:   filter.Get("service"),
 		NodeIDs:      filter.Get("node"),
+		UpToDate:     len(filter.Get("_up-to-date")) != 0,
 	}
 
 	for _, s := range filter.Get("desired-state") {