ocfs2: Use filemap_write_and_wait() instead of write_inode_now()

Since ocfs2 has no ->write_inode method, there's no point in calling
write_inode_now() from ocfs2_cleanup_delete_inode().  Use
filemap_write_and_wait() instead. This helps us to cleanup inode writing
interfaces...

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Joel Becker <jlbec@evilplan.org>