Mounting a ConfigMap with volumes as file fails

Issue

Mounting a ConfigMap and specifying a path for a config file replacement fails with one of the following errors when the goal is to specify a configuration file, not create a directory:

Cannot start service xxxxx: oci runtime error: container_linux.go:247: starting container process caused "container init exited prematurely"

container_linux.go:247: starting container process caused "process_linux.go:364: container init caused \"rootfs_linux.go:54: mounting \\\"/var/lib/origin/openshift.local.volumes/pods/5d7b39aa-99aa-11e9-889a-005056874791/volumes/kubernetes.io~configmap/t9-setenv\\\" to rootfs \\\"/var/lib/docker/overlay2/623548c818d1f06b66ffe57de2a99625c7a64b3ba57fb1756d5b4625633207d2/merged\\\" at \\\"/var/lib/docker/overlay2/623548c818d1f06b66ffe57de2a99625c7a64b3ba57fb1756d5b4625633207d2/merged/app/tomcat/instances/docker/bin/setenv.sh\\\" caused \\\"not a directory\\\"\""

Or, the container will mount properly, but configuration files will not be present. Instead, an "oc rsh" into the pod shows that the path has been created as a directory rather than a configuration file. The deployment should instead overwrite a configuration file as described in the documentation.