nfscl: Fix processing of a rare Rename reply case

When delegations are enabled (they are not by default in
the FreeBSD NFSv4 server), rename will check for and return
delegations. If the second of these DelegReturn operations
were to fail (they rarely do), then the code would not retry
the rename with returning delegations, as it is intended to do.

The patch fixes the problem, since the DelegReturn reply status
is the second iteration of the loop and not the first iteration.

As noted, this bug would have rarely manifested a problem, since
DelegReturn operations do not normally fail.

MFC after: 2 weeks