PVC in OpenShift template uses accessMode ReadWriteMany which causes deployment to fail on AWS

These templates:
https://github.com/jboss-container-images/rhdm-7-openshift-image/blob/7.4.x/templates/rhdm74-authoring-ha.yaml
https://github.com/jboss-container-images/rhdm-7-openshift-image/blob/7.4.x/templates/rhdm74-authoring.yaml

create a PVC for RHDM using access mode ReadWriteMany.

On AWS or any environment that uses persistent storage like EBS that doesn't support this mode, deployment will fail.

The accessModes should be ReadWriteOnce. which is what the template for RHDM 7.5 uses.