send-email: sanitize author when writing From line

sender is now sanitized, but we didn't sanitize author when checking
whether From: line is needed in the message body.

As a result git started writing duplicate From: lines when author
matched sender and has utf8 characters.

Reported-by: SZEDER Gábor <szeder@ira.uka.de>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: SZEDER Gábor <szeder@ira.uka.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

git-send-email.perl

@@ -1258,6 +1258,7 @@ sub send_message {
 	open my $fh, "<", $t or die "can't open file $t";
 
 	my $author = undef;
+	my $sauthor = undef;
 	my $author_encoding;
 	my $has_content_type;
 	my $body_encoding;
@@ -1296,7 +1297,7 @@ sub send_message {
 			}
 			elsif (/^From:\s+(.*)$/i) {
 				($author, $author_encoding) = unquote_rfc2047($1);
-				my $sauthor = sanitize_address($author);
+				$sauthor = sanitize_address($author);
 				next if $suppress_cc{'author'};
 				next if $suppress_cc{'self'} and $sauthor eq $sender;
 				printf("(mbox) Adding cc: %s from line '%s'\n",
@@ -1392,7 +1393,7 @@ sub send_message {
 		$subject = quote_subject($subject, $auto_8bit_encoding);
 	}
 
-	if (defined $author and $author ne $sender) {
+	if (defined $sauthor and $sauthor ne $sender) {
 		$message = "From: $author\n\n$message";
 		if (defined $author_encoding) {
 			if ($has_content_type) {

t/t9001-send-email.sh

@@ -956,7 +956,7 @@ test_expect_success $PREREQ 'utf8 author is correctly passed on' '
 	grep "^From: Füñný Nâmé <odd_?=mail@example.com>" msgtxt1
 '
 
-test_expect_failure $PREREQ 'utf8 sender is not duplicated' '
+test_expect_success $PREREQ 'utf8 sender is not duplicated' '
 	clean_fake_sendmail &&
 	test_commit weird_sender &&
 	test_when_finished "git reset --hard HEAD^" &&