NFS: check xdr_decode for errors

Check if the decoded entry has the eof bit set when returning from xdr_decode
with an error.  If it does, we should set the eof bits in the array before
returning.  This should keep us from looping when we expect more data but the
server doesn't give us anything new.

Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>