Mention OpenShift specific instructions on Bookinfo tutorial (#5429)
Mention OpenShift specific instructions on Bookinfo tutorial (#5429)

It's easy to skip that step, and when deployment fails it will
take some time to people realize what was the mistake.
istio/istio.io,istio/istio.io,istio/istio.io,istio/istio.io,istio/istio.io,istio/istio.io,istio/istio.io