Legacy 4.x localization files should be prefixed by target language
code and then converted as ll-XML if needed.

Change-Id: Ia5919b25e7ea2f9d94d6c1c37d6f440d45cd6961
Reviewed-on: http://review.typo3.org/42118


Reviewed-by: Xavier Perseguers <xavier@typo3.org>
Tested-by: Xavier Perseguers <xavier@typo3.org>