nfs_clrpcops.c: Fix handling of a CreateLayGet reply

Without this patch, the CreateLayGet RPC did not handle a NFSv4.1/4.2
reply for a pNFS server that also issued delegations.

This patch fixes the problem.

Detected at the recent NFSv4 Bakeathon testing event.

This bug would only affect the rare case where the FreeBSD client
is mounted to a pNFS server that issues delegations, where the
"pnfs" mount option is specified.

MFC after: 2 weeks