Fix import path for register_dscm_oc in MockWebServer

import logging, threading

from nbi.service.NbiApplication import NbiApplication

from nbi.service.rest_server.nbi_plugins.dscm_oc import register_dscm_oc

from nbi.service.dscm_oc import register_dscm_oc

from .Constants import LOCAL_HOST, NBI_SERVICE_PORT, NBI_SERVICE_PREFIX_URL