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>