notes: fix malformed tree entry

The mode bits for entries in a tree object should be an octal number
with minimum number of digits.  Do not pad it with 0 to the left.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/notes.c b/notes.c
index 3ba3e6d..a4f9926 100644
--- a/notes.c
+++ b/notes.c
@@ -624,8 +624,8 @@
 		const char *path, unsigned int path_len, const
 		unsigned char *sha1)
 {
-		strbuf_addf(buf, "%06o %.*s%c", mode, path_len, path, '\0');
-		strbuf_add(buf, sha1, 20);
+	strbuf_addf(buf, "%o %.*s%c", mode, path_len, path, '\0');
+	strbuf_add(buf, sha1, 20);
 }
 
 static void tree_write_stack_init_subtree(struct tree_write_stack *tws,