cmd/dockerd: update --ip6tables description to include "experimental"

This feature requires experimental mode to be enabled, so mentioning that
in the flag description.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

cmd/dockerd/config_unix.go

@@ -38,7 +38,7 @@ func installConfigFlags(conf *config.Config, flags *pflag.FlagSet) error {
 	flags.BoolVar(&conf.EnableSelinuxSupport, "selinux-enabled", false, "Enable selinux support")
 	flags.Var(opts.NewNamedUlimitOpt("default-ulimits", &conf.Ulimits), "default-ulimit", "Default ulimits for containers")
 	flags.BoolVar(&conf.BridgeConfig.EnableIPTables, "iptables", true, "Enable addition of iptables rules")
-	flags.BoolVar(&conf.BridgeConfig.EnableIP6Tables, "ip6tables", false, "Enable addition of ip6tables rules")
+	flags.BoolVar(&conf.BridgeConfig.EnableIP6Tables, "ip6tables", false, "Enable addition of ip6tables rules (experimental)")
 	flags.BoolVar(&conf.BridgeConfig.EnableIPForward, "ip-forward", true, "Enable net.ipv4.ip_forward")
 	flags.BoolVar(&conf.BridgeConfig.EnableIPMasq, "ip-masq", true, "Enable IP masquerading")
 	flags.BoolVar(&conf.BridgeConfig.EnableIPv6, "ipv6", false, "Enable IPv6 networking")