NFSv4.1: fix zero value filehandle in post open getattr

Currently, if the OPEN compound experiencing an error and needs to
get the file attributes separately, it will send a stand alone
GETATTR but it would use the filehandle from the results of
the OPEN compound. In case of the CLAIM_FH OPEN, nfs_openres's fh
is zero value. That generate a GETATTR that's sent with a zero
value filehandle, and results in the server returning an error.

Instead, for the CLAIM_FH OPEN, take the filehandle that was used
in the PUTFH of the OPEN compound.

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>