kubeScheduler.usePolicyConfigMap doesn't work duo to a missing flag on kube-scheduler

[waldman]

1. What kops version are you running? The command kops version, will display
   this information.
   1.9.0 alpha

2. What Kubernetes version are you running? kubectl version will print the
   version if a cluster is running or provide the Kubernetes version specified as
   a kops flag.
   1.9.3

3. What cloud provider are you using?
   AWS

4. What commands did you run? What is the simplest way to reproduce this issue?
   I put up a cluster and set the useConfigMap Scheduler option:

  kubeScheduler:
    usePolicyConfigMap: true

With this option set the kube-scheduler breaks duo to the missing --policy-configmap-namespace. This is a bug and here is the report for it on K8s upstream project: kubernetes/kubernetes#61368

5. What happened after the commands executed?
   The cluster get created but kube-scheduler doesn't get up with the following error:

F0319 19:21:47.831522       1 helpers.go:119] error: couldn't get policy config map /scheduler-policy: an empty namespace may not be set when a resource name is provided

6. What did you expect to happen?
   The scheduler to work using the ConfigMap stored at the kube-system namespace.

7. Please provide your cluster manifest. Execute
   kops get --name my.example.com -oyaml to display your cluster manifest.
   You may want to remove your cluster name and other sensitive information.

8. Please run the commands with most verbose logging by adding the -v 10 flag.
   Paste the logs into this report, or in a gist and provide the gist link here.

9. Anything else do we need to know?
   I'm appending a PR with the change shortly

[justinsb]

Believed fixed by #4726 - please reopen if not!

[justinsb]

(& thanks for fixing @waldman :-) )