Teach fmt-patch about --keep-subject

Signed-off-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Junio C Hamano <junkio@cox.net>
diff --git a/log-tree.c b/log-tree.c
index 1ca529d..4a3cd67 100644
--- a/log-tree.c
+++ b/log-tree.c
@@ -46,8 +46,11 @@
 					"Subject: [PATCH %d/%d] ",
 					opt->nr, opt->total);
 			subject = buffer;
-		} else
+		} else if (opt->total == 0)
 			subject = "Subject: [PATCH] ";
+		else
+			subject = "Subject: ";
+
 		printf("From %s  Thu Apr 7 15:13:13 2005\n",
 		       sha1_to_hex(commit->object.sha1));
 	} else {