Message "the cache is not started, can not read objects" when starting the operator

[jpkrohling]

Starting with the Operator SDK 0.12.0 (controller-runtime 0.3.0), the Jaeger Operator shows messages like the following during bootstrap:

WARN[0000] failed to upgrade managed instances           error="the cache is not started, can not read objects"
ERRO[0000] error cleaning orphaned deployment            error="the cache is not started, can not read objects"

This is caused by a change in the controller-runtime, which returns an error when the cache hasn't been started yet. Before this change, the client would just silently fail, meaning that our upgrade mechanism and the routine to clean orphaned deployments wasn't working properly.

To suppress the messages, we downgraded to 0.11.0 in #808, but a proper solution is to run the procedures above only when the cache has started. Determining when it happened is tricky, and it was suggested in the operator-sdk slack channel that we should make use of API clients instead.

[jpkrohling]

cc @rubenvp8510