Suppress message box in case current locale is unsupported or missing in wx

Beremiz can still be translated into it using own locales
available in './locale'.

<?xml version='1.0' encoding='utf-8'?>
<BeremizRoot xmlns:xsd="http://www.w3.org/2001/XMLSchema" URI_location="LOCAL://">
  <TargetType/>
</BeremizRoot>