make git-send-email.perl handle email addresses with no names when Email::Valid is...

make git-send-email.perl handle email addresses with no names when Email::Valid is present

When using git-send-email.perl on a changeset that has:
	Cc: <stable@kernel.org>
in the body of the description, and the Email::Valid perl module is
installed on the system, the email address will be deemed "invalid" for
some reason (Email::Valid isn't smart enough to handle this?) and
complain and not send the address the email.

Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>