nfs: initiate returning delegation when reclaiming one that's been recalled

When reclaiming a delegation via CLAIM_PREVIOUS open, the server can
indicate that the delegation has been recalled since it was issued by
setting the "recalled" flag in the delegation.

Ensure that we respect the flag by initiating a delegation return when
it is set.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>