* fs/hfsplus.c (grub_hfsplus_read_block): Fixed a memory leak.
(grub_hfsplus_iterate_dir): Reordered to skip unknown nodes. Also,
skip a node whose name is obviously invalid as UTF-16,
i.e. contains a NUL character. Stop the iteration when the last
directory entry is found. Instead of using the return value of
grub_hfsplus_btree_iterate_node, store the value in RET and use
it, because the iterator can be stopped by the last directory
entry.