update link comments

Signed-off-by: Wen Cheng Ma <wenchma@cn.ibm.com>

daemon/container_operations.go

@@ -167,7 +167,7 @@ func (daemon *Daemon) buildSandboxOptions(container *container.Container, n libn
 		libnetwork.OptionPortMapping(pbList),
 		libnetwork.OptionExposedPorts(exposeList))
 
-	// Link feature is supported only for the default bridge network.
+	// Legacy Link feature is supported only for the default bridge network.
 	// return if this call to build join options is not for default bridge network
 	if n.Name() != defaultNetName {
 		return sboxOptions, nil

daemon/daemon_unix.go

@@ -977,7 +977,6 @@ func (daemon *Daemon) registerLinks(container *container.Container, hostConfig *
 		}
 		child, err := daemon.GetContainer(name)
 		if err != nil {
-			//An error from daemon.GetContainer() means this name could not be found
 			return fmt.Errorf("Could not get container for %s", name)
 		}
 		for child.HostConfig.NetworkMode.IsContainer() {