nfsd: CLOSE SHOULD return the invalid special stateid for NFSv4.x (x>0)

[ Upstream commit fb500a7cfee7f2f447d2bbf30cb59629feab6ac1 ]

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>