automated tests for boundary cases

not sure if it will be easy or make sense to add boundary cases in to the openshift
e2e CI framework or not. Maybe an investigation spike should be done first?

cases to cover (there may be more)

• exhaust pod ip's available until pod creation is rejected
  • expand CIDR and verify more pods can be created
• assuming X nodes, create a CIDR w/ appropriate hostsubnet such that a new node cannot be added
  • validate a smaller CIDR config is rejected