* luci/i18n: rename *.pt_br.* to *.pt-br.*, extend luci.i18n to convert "_" to "-" in language tags

libs/web/luasrc/i18n.lua

@@ -45,7 +45,7 @@ end
 -- @param force	Force reload even if already loaded (optional)
 -- @return		Success status
 function load(file, lang, force)
-	lang = lang or ""
+	lang = lang and lang:gsub("_", "-") or ""
 	if force or not loaded[lang] or not loaded[lang][file] then
 		local f = loadfile(i18ndir .. file .. "." .. lang .. ".lua")
 		if f then
@@ -75,7 +75,7 @@ end
 --- Set the context default translation language.
 -- @param lang	Two-letter language code
 function setlanguage(lang)
-	context.lang = lang
+	context.lang = lang:gsub("_", "-")
 end
 
 --- Return the translated value for a specific translation key.