NFS fix COMMIT after COPY

Fix a typo in the commit e0926934
"NFS append COMMIT after synchronous COPY"

Reported-by: Eryu Guan <eguan@redhat.com>
Fixes: e0926934 ("NFS append COMMIT after synchronous COPY")
Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Tested-by: Eryu Guan <eguan@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>