fix autofs/afs/etc. magic mountpoint breakage

We end up trying to kfree() nd.last.name on open("/mnt/tmp", O_CREAT)
if /mnt/tmp is an autofs direct mount.  The reason is that nd.last_type
is bogus here; we want LAST_BIND for everything of that kind and we
get LAST_NORM left over from finding parent directory.

So make sure that it *is* set properly; set to LAST_BIND before
doing ->follow_link() - for normal symlinks it will be changed
by __vfs_follow_link() and everything else needs it set that way.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
static struct dentry *lookup_hash(struct nameidata *nd)
{
	int err;

	err = exec_permission(nd->path.dentry->d_inode);
	if (err)
		return ERR_PTR(err);
	return __lookup_hash(&nd->last, nd->path.dentry, nd);
}

static struct dentry *lookup_hash(struct nameidata *nd)
{
	int err;

	err = exec_permission(nd->path.dentry->d_inode);
	if (err)
		return ERR_PTR(err);
	return __lookup_hash(&nd->last, nd->path.dentry, nd);
}
