Checking cluster status before actions

* add checking if cluster is operational or error state
  when calling an action to run OSTF tests through fuelclient
* add checking of cluster status when running network
  verification in nailgun

Change-Id: I3f40fb0e0b3d589834c242e73e9f8250daf4e05f
Closes-Bug: #1337887
Closes-Bug: #1337884
Merge "Checking cluster status before actions"