tosca parser does not raise exception even with wrong type definition

[yong sheng gong]

https://review.openstack.org/#/c/435187/9/tacker/vnfm/tosca/lib/tacker_defs.yaml@1

we have the type is put under policies even though it is actually not a policy:

  tosca.datatypes.tacker.VirtualIP:
    properties:
      ip_address:
        type: string
        required: true
        description: The virtual IP address allowed to be paired with.
      mac_address:
        type: string
        required: false
        description: The mac address allowed to be paired with specific virtual IP.