[imp] IMP Header folding erroneous -> exim corrupts email (see Bug #10696)

[Günter Merz]

Hello,

a git pull on the development repository caused the emails sent by imp
to be corrupted.

I tracked the issue down to:

   Bug #10696: Sendmail driver/message data EOL issue

which is marked as 'Resolved'.

The the result of the changes introduced in this bug results in emails
that have generally a '\n' line ending with the exception of folded
header lines: those get '\r\n'.

As a consequence, exim (invoked by '/usr/lib/sendmail -oi') indents
the content of my email with one whitespace and adds its own header
lines.

Reverting the changes (changing 'canonical' to false) resolves this
problem.

I have to admit, I don't see the benefit of the changes.

Can anyone explain or can the changes be reversed?