Comment 5 for bug 1770932

We only had this issue after this change:
https://github.com/openstack/ironic/commit/228a2a7885e1b04d4180fe8daa2992884decaf6d

since it is present in branches "stable/queens" and was backported to "stable/pike" (https://github.com/openstack/ironic/commit/78c4d016461bf88030e4e304b912bd7a1f711815)

we need to do the same fix master (done) and backport to queens and pike.