nfs: use new admin command interface

Acked-by: Albert Rossi
Target: master
Require-book: no
Require-notes: no
nfs: add a command to reset pool's device id

device id used to map pool with data server know by client.
In RHEL6 and clones, if sore some reason pools get blacklisted,
the we have to restart door, pool or client. Added command
allowes door to 'forget' the pool and generate new id.

Acked-by: Albert Rossi
Target: master
Require-book: no
Require-notes: no