Bug 28729: Make Koha::Email->send_or_die handle returnpath

Bug 28729: Make Koha::Email->send_or_die handle returnpath

Koha used to rely on Mail::Sendmail for sending emails. As an SMTP
client, the library would extract the from address from the Sender
header to pass along in the MAIL FROM: field of the SMTP protocol [1].

This was overlooked when we moved to Email::Stuffer/Email::Simple and
there's a different behavior as it expects the envelope to be passed and
falls back to extracting the 'From' header when said envelope is not
found [2].

This patchset re-introduces the behavior from Mail::Sendmail by
overriding the send_or_die method locally (in Koha::Email) and doing the
right thing.

Unless an explicit {from} parameter is passed, it extracts the MAIL FROM
envelope from the Sender header, as Mail::Sendmail did, and calls
$self->SUPER::send_or_die with the right parameters.

To test:
1. Apply the unit tests
2. Run:
   $ kshell
   k$ prove t/Koha/Email.t
   => FAIL: Sender is not handled correctly!
3. Apply this patch
4. Repeat 2
   => SUCCESS: Tests pass!
   The from parameter is correct!
   No Sender header sent!
5. Sign off :-D

[1] https://metacpan.org/dist/Mail-Sendmail/source/lib/Mail/Sendmail.pm#L284
[2] https://metacpan.org/pod/Email::Sender::Manual::QuickStart#envelope-information

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
AMENDED (SHORTENED)
-        my @headers = $self->email->header_str_pairs;
-        foreach my $pair ( pairs @headers ) {
-            my ( $header, $value ) = @$pair;
-            $args->{from} = $value if $header eq 'Sender';
-        }
-
-        # Remove the Sender header
-        $self->email->header_str_set('Sender');
+        $args->{from} = $self->email->header_str('Sender');
+        $self->email->header_str_set('Sender'); # remove Sender header

Tested with same results (scrambled domains):
From: noreply@mydevserver.com
Cc: marcel@email.nl
To: test@somewhere.nl
Reply-To: bieb@mydevserver.com
Return-Path: postmaster@mydevserver.com

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>