NFS: More O_DIRECT accounting fixes for error paths

If we hit a fatal error when retransmitting, we do need to record the
removal of the request from the count of written bytes.

Fixes: 031d73ed

 ("NFS: Fix O_DIRECT accounting of number of bytes read/written")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>