wizard: Check language is supported

Otherwise it may raise InvalidRegistryValue on first start

src/i18n.py

@@ -50,6 +50,7 @@ MSGSTR = 'msgstr "'
 FUZZY = '#, fuzzy'
 
 currentLocale = 'en'
+SUPPORTED_LANGUAGES = ['de', 'en', 'es', 'fi', 'fr', 'it']
 
 class PluginNotFound(Exception):
     pass
@@ -71,7 +72,7 @@ def import_conf():
     global conf
     conf = __import__('supybot.conf').conf
     class Languages(conf.registry.OnlySomeStrings):
-        validStrings = ['de', 'en', 'es', 'fi', 'fr', 'it']
+        validStrings = SUPPORTED_LANGUAGES
         errormsg = 'Value should be a supported language (%s), not %%r' % (
             ', '.join(validStrings))
     conf.registerGlobalValue(conf.supybot, 'language',

src/scripts/limnoria_wizard.py

@@ -253,7 +253,8 @@ def _main():
     language. This can be changed at any time. You need to answer with a short
     id for the language, such as 'en', 'fr', 'it' (without the quotes). If
     you want to use English, just press enter.""")
-    language = something('What language do you want to use?', default='en')
+    language = expect('What language do you want to use?',
+                      i18n.SUPPORTED_LANGUAGES, default='en')
 
     class Empty:
         """This is a hack to allow the i18n to get the current language, before