NFSv41: Clean up slot table management

We no longer need to maintain a distinction between nfs41_sequence_done and
nfs41_sequence_free_slot.

This fixes a number of slot table leakages in the NFSv4.1 code.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

diff --cc fs/nfs/internal.h
Simple merge

diff --cc fs/nfs/nfs4proc.c
Simple merge

diff --cc fs/nfs/read.c
Simple merge

diff --cc fs/nfs/unlink.c
Simple merge

diff --cc fs/nfs/write.c
Simple merge