MFC: r317276
Don't set ND_NOMOREDATA for a failed Setattr operation (NFSv4).

The NFSv4 Setattr operation always has reply data even when it fails,
so don't set the ND_NOMOREDATA for it. This would only affect unusual
cases where Setattr fails and the RPC code wants to parse the rest of
the compound. Detected during recent development related to the pNFS server.