Fix ZFS to OpenZFS on the front page
Created by: shmerl
Right now the site says: ZFS Filesystem Support (WIP)
It surely refers to OpenZFS which is a different filesystem than ZFS. OpenZFS is FOSS and it already diverged from closed source ZFS owned by Oracle. They are incompatible and there is no goal to keep them compatible in the future. So to avoid confusion, please call it with correct name - OpenZFS.