t4013 diff format tests update

This changes one test commit in the sequence to have more than
one lines of commit log.  A few output formats (--pretty=email
aka format-patch and --pretty=oneline) need to behave
differently on single and multi-line log, and this change will
help catching breakages.

Signed-off-by: Junio C Hamano <junkio@cox.net>
diff --git a/t/t4013/diff.format-patch_--stdout_initial..master^ b/t/t4013/diff.format-patch_--stdout_initial..master^
index e56dd98..4e87689 100644
--- a/t/t4013/diff.format-patch_--stdout_initial..master^
+++ b/t/t4013/diff.format-patch_--stdout_initial..master^
@@ -1,8 +1,10 @@
 $ git format-patch --stdout initial..master^
-From 7952a93e09bf565b5592766a438b40cd81f4846f Mon Sep 17 00:00:00 2001
+From 1bde4ae5f36c8d9abe3a0fce0c6aab3c4a12fe44 Mon Sep 17 00:00:00 2001
 From: A U Thor <author@example.com>
 Date: Mon, 26 Jun 2006 00:01:00 +0000
 Subject: [PATCH] Second
+
+This is the second commit.
 ---
  dir/sub |    2 ++
  file0   |    3 +++
@@ -42,7 +44,7 @@
 g-i-t--v-e-r-s-i-o-n
 
 
-From 889b315013ef9f2e2f90aa0b054b267c8a557847 Mon Sep 17 00:00:00 2001
+From 9a6d4949b6b76956d9d5e26f2791ec2ceff5fdc0 Mon Sep 17 00:00:00 2001
 From: A U Thor <author@example.com>
 Date: Mon, 26 Jun 2006 00:02:00 +0000
 Subject: [PATCH] Third