mailinfo: accept >From in message header

mailinfo: accept >From in message header

Mail I get sometimes has multiple From lines, like this:

    From Majordomo@vger.kernel.org  Thu Jul 27 16:39:36 2006
    >From mtsirkin  Thu Jul 27 16:39:36 2006
    Received: from yok.mtl.com [10.0.8.11]
    ...

which confuses git-mailinfo since that does not recognize >From
as a valid header line.

This patch makes it recognize >From XXX as a valid header line.

Signed-off-by: Michael S. Tsirkin <mst@mellanox.co.il>
Signed-off-by: Junio C Hamano <junkio@cox.net>