Merge pull request #6 from mvidner/Code-11-SP3

parallel NFS: pNFS aka NFS4.1. FATE#312259
AutoYaST: tests for SP2 schema.
AutoYaST: fix to allow NFS4 options (FATE#312242, bnc#457981)

Backported from 29e91e5e406e7ef9647810b92b462c478d46a9c9
BUT! changed the schema to keep compatibility with SLE11-SP2.

Nfs.ycp: removing a public function Nfs::Set which is not used
anywhere else. Namely not in

- autoyast2
- yast2-backup
- yast2-installation
- yast2-nfs-client
- yast2-nfs-server
.changes
Added option for enabling NFS4 GSS (FATE#312242, bnc#681190)

backported from 29f5fb6c167ca097784624cb1e581cc569e1ef9c