The version of cloud-init included with CentOS7.5 (0.7.9-24)
fails to assign an IP address on VLAN subinterfaces. This
workaround upgrades cloud-init to 18.2 using a private
repository.
Story: 2002610
Task: 22229
Change-Id: Idc570b9ca7558dfd42246c74b1ec0331011d692f