wait for service to restart

[johnstudarus]

Starting up servers right after the cloud is built may fail since not all services have had a chance to start. A simple "sleep 60" solves the problem but it would be more elegant to poll for the awaiting services.

See:
https://github.com/packet-labs/OpenStackOnPacket/blob/master/OpenStackSampleWorkload.tf#L93
and
https://github.com/packet-labs/OpenStackOnPacket/blob/master/OpenStackSampleWorkload.tf#L63