Btrfs: kill unused argument of btrfs_pin_extent_for_log_replay

Argument 'trans' is not used any more.

Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 7de720d..deb7f66 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -278,8 +278,7 @@
 			      struct walk_control *wc, u64 gen)
 {
 	if (wc->pin)
-		btrfs_pin_extent_for_log_replay(wc->trans,
-						log->fs_info->extent_root,
+		btrfs_pin_extent_for_log_replay(log->fs_info->extent_root,
 						eb->start, eb->len);
 
 	if (btrfs_buffer_uptodate(eb, gen, 0)) {