POST preload data to GENERIC-RESOURCE-API and verify that data is loaded correctly.

Test Instructions:

1) Verify preload data is empty by running:
curl -k -uadmin:<password> -H "Content-Type: application/json" https://<worker-vm-ip-address>:30267/restconf/config/GENERIC-RESOURCE-API:preload-information/
(should return error indicating model does not exist)
2) Insert network preload data by running:
curl -k -uadmin:<password> -H "Content-Type: application/json" -X POST https://<worker-vm-ip-address>:30267/restconf/operations/GENERIC-RESOURCE-API:preload-network-topology-operation -X POST -d@preload1-rpc-network.json
3) Verify that preload data loaded by running step 1 again and verifying there is 1 network preload entry.
4) Insert vf-module preload data by running:
curl -k -uadmin:<password> -H "Content-Type: application/json" -X POST https://<worker-vm-ip-address>30267/restconf/operations/GENERIC-RESOURCE-API:preload-vf-module-topology-operation -X POST -d@preload1-rpc-vfmodule.json
5) Rerun step 1 and verify that preload contains 1 network and 1 vfmodule entry.