Comment 6 for bug 1643210

Suppose sender is a member who set preference language ja, the list language is french and original From: is 'From: =?UTF-8?B?5LqM5pyoIOmdluS7gQ==?= <email address hidden>'.
The translation of '%(realname)s via %(lrn)s' is taken from sender's language context, ja, and its charset is euc-jp. The display name of original from cannot encode to iso-8859-1 entirely and translation of 'via' part is miss interpreted as iso-8859-1. For the latter problem, we should encode it to encoding of sender's preference language (at least the translation of 'via' part).

I don't want to break the realname even if it cannot be encoded to his/her preferred language's encoding, so I select to abandon to translate 'via' part for simple fix. This will occur in language settings that of charset/encoding is not UTF-8.