add luacheck and fix unused variable util

.luacheckrc

@@ -0,0 +1,106 @@
+codes = true
+std = "min"
+self = false
+
+new_read_globals = {
+	"getfenv",
+	"setfenv",
+	"unpack",
+}
+
+include_files = {
+	"**/*.lua",
+	"package/**/files/lib/gluon/ebtables/*",
+	"package/**/luasrc/**/*",
+	"targets/*",
+}
+
+exclude_files = {
+	"**/*.mk",
+}
+
+files["scripts/check_site.lua"] = {
+	allow_defined = true,
+	module = true,
+}
+
+files["**/check_site.lua"] = {
+	new_read_globals = {
+		"alternatives",
+		"extend",
+		"in_domain",
+		"in_site",
+		"need",
+		"need_alphanumeric_key",
+		"need_array",
+		"need_array_of",
+		"need_boolean",
+		"need_chanlist",
+		"need_domain_name",
+		"need_number",
+		"need_one_of",
+		"need_string",
+		"need_string_array",
+		"need_string_array_match",
+		"need_string_match",
+		"need_table",
+		"need_value",
+		"obsolete",
+		"table_keys",
+		"this_domain",
+	},
+}
+
+files["**/files/lib/gluon/ebtables/*"] = {
+	new_read_globals = {
+		"chain",
+		"rule",
+	},
+	max_line_length = false,
+}
+
+files["**/luasrc/lib/gluon/config-mode/*"] = {
+	globals = {
+		"DynamicList",
+		"Flag",
+		"Form",
+		"i18n",
+		"ListValue",
+		"renderer.render",
+		"renderer.render_string",
+		"Section",
+		"TextValue",
+		"_translate",
+		"translate",
+		"translatef",
+		"Value",
+	},
+}
+
+files["**/luasrc/lib/gluon/**/controller/*"] = {
+	new_read_globals = {
+		"_",
+		"alias",
+		"call",
+		"entry",
+		"model",
+		"node",
+		"template",
+	},
+}
+
+files["targets/*"] = {
+	new_read_globals = {
+		"config",
+		"defaults",
+		"device",
+		"env",
+		"envtrue",
+		"exec_capture_raw",
+		"factory_image",
+		"no_opkg",
+		"packages",
+		"sysupgrade_image",
+		"try_config",
+	},
+}

gluon-ssid-changer/luasrc/lib/gluon/config-mode/model/admin/ssid-changer.lua

@@ -1,5 +1,4 @@
 local uci = require('simple-uci').cursor()
-local util = require 'gluon.util'
 
 local pkg_i18n = i18n 'gluon-ssid-changer'