Btrfs: Fix variable init during csum creation

Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
index f861bd5..6dbe88b 100644
--- a/fs/btrfs/file-item.c
+++ b/fs/btrfs/file-item.c
@@ -325,6 +325,7 @@
 	item = btrfs_lookup_csum(trans, root, path, objectid, offset, 1);
 	if (!IS_ERR(item)) {
 		leaf = path->nodes[0];
+		ret = 0;
 		goto found;
 	}
 	ret = PTR_ERR(item);