i18n - return default locale when current language is not set

to avoid reinitialization in testsuite

src/ruby/ycp/i18n.rb

@@ -7,6 +7,7 @@ module ClassMethods
 
       #TODO load alternative in development recent translation
       LOCALE_DIR = "/usr/share/YaST2/locale"
+      DEFAULT_LOCALE = "en_US"
 
       def textdomain domain
         # TODO FIXME:
@@ -54,7 +55,7 @@ def combined_repositories
       def available_locales
         # the first item is used as the fallback
         # when the requested locale is not available
-        locales = [ "en_US" ]
+        locales = [ DEFAULT_LOCALE ]
 
         Dir["#{LOCALE_DIR}/*"].each do |f|
           locale_name = File.basename f
@@ -69,6 +70,8 @@ def current_language
         # like ".UTF-8" if present)
         lang = WFM.GetLanguage.gsub(/\..*$/, "")
 
+        return DEFAULT_LOCALE if lang.empty?
+
         # remove the country suffix if that locale is not available
         # e.g. there are "pt_BR" and "de" translations (there is generic "pt" but no "de_DE")
         lang.gsub!(/_.*$/, "") if FastGettext.available_locales.nil? || !FastGettext.available_locales.include?(lang)