git-send-email: Remove redundant Reply-To header

There is no sense in duplicating the sender address in Reply-To as it's
already provided in the From header.

Signed-off-by: Alp Toker <alp@atoker.com>
Signed-off-by: Junio C Hamano <junkio@cox.net>

git-send-email.perl

@@ -435,7 +435,6 @@ sub send_message
 To: $to
 Cc: $cc
 Subject: $subject
-Reply-To: $from
 Date: $date
 Message-Id: $message_id
 X-Mailer: git-send-email $gitversion