Since change https://gerrit.fd.io/r/6098, VPP now has strict reference checking when removing bridge domains.

Given the following configuration:
1. enable Lisp
2. add locator set
3. create bridge domain
4. add remote bridge domain mapping
5. remove the mapping
6. remove the bridge domain

Step 6 fails with VppCallbackException: vppApi.bridge_domain_add_del_reply failed with error code: -120 (BD_IN_USE, -120, "Bridge domain has member interfaces")

The mapping that referenced the bridge domain was deleted, so it should be possible to delete the bridge domain.