admindb uses wrong language in subscription approval result page body

[Yasuhito FUTATSUKI at POEM]

If
* a list allows to use different language from list.preferred_language
* its policy requires admin approval for subscribes
* it set to send welcome message to new member
and admin approves subscription request of user who select his language different from list's on Web UI, the result page body of admindb uses charset of user's language while the header declare to use charset of the lists, thus causes 'Mojibake'.

I'm very sorry, but I have not read the code arround it yet, so I report symptom only right now.

[Yasuhito FUTATSUKI at POEM (futatuki)]

This is caused by MailList.ApprovedAddMember(), which is not preserve translation object on sending welcome message by using Deliverer.SendSubscribeAck().

[Mark Sapiro (msapiro)]

Thank you very much for the report and patch.