Nightly 05/01/18 5-15-NFS-Datastore: cluster setup nimbus-ctl ip timed out

[AngieCris]

Nightly 05/01/18
VC 6.0
Test suite: 5-15-NFS-Datastore
Test step: Simple VC Cluster Setup

Every one of the nimbus-ctl ip failed with empty output:

link to log:
https://storage.cloud.google.com/vic-ci-logs/vic_nightly_logs_2018-05-01-20-32-56.zip?authuser=1

Cc: @mhagen-vmware