nfscl: Modify Close RPC so that it does not use "owner" for NFSv4.1/4.2

This patch modifies the function that does the Close RPC (nfsrpc_closerpc)
so that it does not use the open_owner (nfso_own) for NFSv4.1/4.2.
Use of the seqid in the open_owner structure is only needed for NFSv4.0.
Same applies to a NFSERR_STALESTATEID reply, which should only happen
for NFSv4.0. This allows nfsrpc_closerpc() to be called when nfso_own
is no longer valid. This, in turn, allows nfsrpc_closerpc() to be called
after the shared lock on the clientID is released, for NFSv4.1/4.2.

This is being done to prepare the code for a future patch that fixes
the case where an NFSv4.1/4.2 server replies NFSERR_DELAY to a Close
operation.

MFC after: 2 week