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.log_-SF_-p_master b/t/t4013/diff.log_-SF_-p_master
index db2264c..5e32438 100644
--- a/t/t4013/diff.log_-SF_-p_master
+++ b/t/t4013/diff.log_-SF_-p_master
@@ -1,5 +1,5 @@
 $ git log -SF -p master
-commit 889b315013ef9f2e2f90aa0b054b267c8a557847
+commit 9a6d4949b6b76956d9d5e26f2791ec2ceff5fdc0
 Author: A U Thor <author@example.com>
 Date:   Mon Jun 26 00:02:00 2006 +0000