In order to enable migration support, we will want to move some of the
structures that are subject to migration into the struct nfs_server.
In particular, if we are to move the state_owner and state_owner_id to
being a per-filesystem structure, then we should label the resulting
open/lock owners with a per-filesytem label to ensure global uniqueness.

This patch does so by adding the super block s_dev to the open/lock owner
name.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>