store: set nodegroup last activity

Signed-off-by: CrazyMax <crazy-max@users.noreply.github.com>

store/storeutil/storeutil.go

@@ -85,7 +85,7 @@ func GetNodeGroup(txn *store.Txn, dockerCli command.Cli, name string) (*store.No
 	}
 	for _, l := range list {
 		if l.Name == name {
-			return &store.NodeGroup{
+			ng = &store.NodeGroup{
 				Name: name,
 				Nodes: []store.Node{
 					{
@@ -93,8 +93,11 @@ func GetNodeGroup(txn *store.Txn, dockerCli command.Cli, name string) (*store.No
 						Endpoint: name,
 					},
 				},
-				DockerContext: true,
-			}, nil
+			}
+			if ng.LastActivity, err = txn.GetLastActivity(ng); err != nil {
+				return nil, err
+			}
+			return ng, nil
 		}
 	}