NFSv4: Fix reboot recovery in copy offload

commit 9d8cacbf5636657d2cd0dda17438a56d806d3224 upstream.

Copy offload code needs to be hooked into the code for handling
NFS4ERR_BAD_STATEID by ensuring that we set the "stateid" field
in struct nfs4_exception.

Reported-by: Olga Kornievskaia <aglo@umich.edu>
Fixes: 2e72448b ("NFS: Add COPY nfs operation")
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>