#28 mails are being duplicated with md5 due to "Date: " mangling

[Tomas Pospisek]

When transferring a message to a mbox, mailsync will apparently fix up the "Date: " header to it's own canonical format.

That implies, when making a md5 hash, that at this point includes the "Date: " header, the md5 sums of a mail saved on lets say an IMAP server and the local inbox will differ.