ext2fs: implement dir entry creation in htree directories
Implement proper creation of new directory entries in htree directories
in ext2fs_link(). So far we just cleared EXT2_INDEX_FL and treated
directory as unindexed however this results in mismatched checksums if
metadata checksums are in use because checksums are placed in different
places depending on htree node type.
Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Theodore Ts'o <tytso@mit.edu>