MultiCloud plugin cannot load VF Module artifacts

As part of consistent ID of cloud region test, it is expected that multicloud plugin could load the VF module artifacts from SDC by multicloud artifactbroker for instantiating a workload over target cloud region.
The test case is to instantiate a Heat stack over OpenStack cloud region.
The test results indicate that multicloud openstack plugin cannot load the VF module artifacts (base_vcpe_vgw.yaml/env in this test):
2019-05-27 05:33:16|||||starlingx_base.resource.infra_workload||139944706603880||openstack_template_update||ERROR||template_update fails: safe_load() got an unexpected keyword argument 'Loader'||||requestID=847d9270-800d-3ef7-9e9d-37d0e0d5e5c9 invocationID=fd548b2f-afbb-4624-a096-d045e8a37437 serviceName=multicloud-titaniumcloud serviceIP=onap-dev1