Bug 28023: Fix Reply-To typo

This patch fixes a typo making the header useless.

To test:
1. Apply the regression tests patch
2. Run:
   $ kshell
  k$ prove t/Koha/Email.t
=> FAIL: The Reply-To header is not being set!
3. Apply this patch
4. Repeat 2
=> SUCCESS: Tests pass! the header is set!
5. Sign off :-D

Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>

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

Koha/Email.pm

@@ -120,7 +120,7 @@ sub create {
 
     my $email = $self->SUPER::new( $args );
 
-    $email->header( 'ReplyTo', $addresses->{reply_to} )
+    $email->header( 'Reply-To', $addresses->{reply_to} )
         if $addresses->{reply_to};
 
     $email->header( 'Sender'       => $addresses->{sender} ) if $addresses->{sender};