The commit 33db4125 ("openvswitch: Rename LABEL->LABELS") left
over an old OVS_CT_ATTR_LABEL instance, fix it.

Fixes: 33db4125 ("openvswitch: Rename LABEL->LABELS")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Acked-by: Joe Stringer <joe@ovn.org>
Signed-off-by: David S. Miller <davem@davemloft.net>