11.2: set max diskspace 98% does not seem to get saved into pool setup file

After installing 11.2 I observe this:

from pool admin interface:
```
>set max diskspace 98%
> save
```

but:

```
# grep -c 'set max diskspace' setup
0
```

setting is not saved into setup file. 

Adding 
```
set max diskspace 98%
```
to setup file manually, then 
```
reload -yes
save
```
ends up in wiping out of that line from setup file.
