luci-base: add default value options dhcp hostname

Signed-off-by: Florian Eckert <fe@dev.tdt.de>

modules/luci-base/htdocs/luci-static/resources/protocol/dhcp.js

@@ -20,6 +20,9 @@ return network.registerProtocol('dhcp', {
 		var dev = this.getL2Device() || this.getDevice(), o;
 
 		o = s.taboption('general', form.Value, 'hostname', _('Hostname to send when requesting DHCP'));
+		o.default = '';
+		o.value('', 'Send the hostname of this device');
+		o.value('*', 'Do not send a hostname');
 		o.datatype    = 'or(hostname, "*")';
 		o.load = function(section_id) {
 			return callFileRead('/proc/sys/kernel/hostname').then(L.bind(function(hostname) {