Comment 1 for bug 1651456

After https://review.openstack.org/340762 gets in the serializer could return null for ethtool/offload values which results in the astute.yaml on nodes:
...
offload:
  generic-receive-offload: null
  generic-segmentation-offload: null
  rx-all: null
  rx-checksumming: null
  rx-fcs: null
  rx-vlan-offload: null
  scatter-gather: null
  tcp-segmentation-offload: null
  tx-checksum-ip-generic: null
  tx-checksumming: null
  tx-nocache-copy: null
  tx-scatter-gather: null
  tx-tcp-segmentation: null
...