Bug 1634700

Description of problem:

When upgrading from Red Hat OpenShift Container Platform 3.9 to Red Hat OpenShift Container Platform 3.10, the upgrade playbook is failing because `runtime-config: ''` is added to `master-config.yaml as per https://github.com/openshift/openshift-ansible/blob/release-3.10/roles/openshift_control_plane/tasks/upgrade.yml#L132

F0928 10:01:42.736248       1 start_api.go:68] could not load config file "/etc/origin/master/master-config.yaml" due to an error: error reading config: [pos 4311]: only encoded map or array can be decoded into a slice (6)
[root@master01 ~]# master-logs controllers controllers
F0928 10:01:42.737000       1 start_controllers.go:67] could not load config file "/etc/origin/master/master-config.yaml" due to an error: error reading config: [pos 4311]: only encoded map or array can be decoded into a slice (6)

When checking, it was found that `runtime-config: ''` needs to be replaced with `runtime-config: []` as this is what is expected. Once this is done manually, everything is started and the upgrade processes without issue.

Version-Release number of selected component (if applicable):

 - atomic-openshift-3.10.45-1.git.0.3b98bf6.el7

How reproducible:

 - Always, when `runtime-config` is set to `apis/settings.k8s.io/v1alpha1=true`

Steps to Reproduce:
1. Upgrading from Red Hat OpenShift Container Platform 3.9 to 3.10 as per https://docs.openshift.com/container-platform/3.10/upgrading/automated_upgrades.html#upgrading-control-plane-nodes-separate-phases

Actual results:

Upgrade is failing as the Master-API does not restart because of syntax failure.

F0928 10:01:42.736248       1 start_api.go:68] could not load config file "/etc/origin/master/master-config.yaml" due to an error: error reading config: [pos 4311]: only encoded map or array can be decoded into a slice (6)
[root@master01 ~]# master-logs controllers controllers
F0928 10:01:42.737000       1 start_controllers.go:67] could not load config file "/etc/origin/master/master-config.yaml" due to an error: error reading config: [pos 4311]: only encoded map or array can be decoded into a slice (6)

Expected results:

No error reported and upgrade to complete without an issue being reported

Additional info:

https://bugzilla.redhat.com/show_bug.cgi?id=1633383 could be of interest here as it also talk about this part of the configuration.

Description of problem:

Version-Release number of the following components:
rpm -q openshift-ansible
rpm -q ansible
ansible --version

How reproducible:

Steps to Reproduce:
1.
2.
3.

Actual results:
Please include the entire output from the last TASK line through the end of output if an error is generated

Expected results:

Additional info:
Please attach logs from ansible-playbook with the -vvv flag