Remove log warning on task update

This warning appears in the course of normal use of swarm mode. Since
it's meant more as an internal TODO than something which should be
exposed to a user, remove the log message.

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

daemon/cluster/executor/container/controller.go

@@ -60,7 +60,6 @@ func (r *controller) ContainerStatus(ctx context.Context) (*api.ContainerStatus,
 
 // Update tasks a recent task update and applies it to the container.
 func (r *controller) Update(ctx context.Context, t *api.Task) error {
-	log.G(ctx).Warnf("task updates not yet supported")
 	// TODO(stevvooe): While assignment of tasks is idempotent, we do allow
 	// updates of metadata, such as labelling, as well as any other properties
 	// that make sense.