NFS: Introduce a vector of migration recovery ops

The differences between minor version 0 and minor version 1
migration will be abstracted by the addition of a set of migration
recovery ops.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2 files changed