nilfs2: remove nilfs_bmap_delete_block

nilfs_bmap_delete_block() is a wrapper function calling
nilfs_btnode_delete().  This removes it for simplicity.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
diff --git a/fs/nilfs2/btree.c b/fs/nilfs2/btree.c
index 102e218..61e70d7 100644
--- a/fs/nilfs2/btree.c
+++ b/fs/nilfs2/btree.c
@@ -1026,7 +1026,7 @@
 						    &path[level].bp_newreq);
  err_out_child_node:
 	for (level--; level > NILFS_BTREE_LEVEL_DATA; level--) {
-		nilfs_bmap_delete_block(&btree->bt_bmap, path[level].bp_sib_bh);
+		nilfs_btnode_delete(path[level].bp_sib_bh);
 		btree->bt_bmap.b_pops->bpop_abort_alloc_ptr(
 			&btree->bt_bmap, &path[level].bp_newreq);
 
@@ -1220,7 +1220,7 @@
 	unlock_buffer(path[level].bp_bh);
 	unlock_buffer(path[level].bp_sib_bh);
 
-	nilfs_bmap_delete_block(&btree->bt_bmap, path[level].bp_bh);
+	nilfs_btnode_delete(path[level].bp_bh);
 	path[level].bp_bh = path[level].bp_sib_bh;
 	path[level].bp_sib_bh = NULL;
 	path[level].bp_index += nilfs_btree_node_get_nchildren(btree, left);
@@ -1251,7 +1251,7 @@
 	unlock_buffer(path[level].bp_bh);
 	unlock_buffer(path[level].bp_sib_bh);
 
-	nilfs_bmap_delete_block(&btree->bt_bmap, path[level].bp_sib_bh);
+	nilfs_btnode_delete(path[level].bp_sib_bh);
 	path[level].bp_sib_bh = NULL;
 	path[level + 1].bp_index++;
 }
@@ -1275,7 +1275,7 @@
 	nilfs_btree_node_move_left(btree, root, child, n);
 	unlock_buffer(path[level].bp_bh);
 
-	nilfs_bmap_delete_block(&btree->bt_bmap, path[level].bp_bh);
+	nilfs_btnode_delete(path[level].bp_bh);
 	path[level].bp_bh = NULL;
 }