ConfigMap doesn't work in 3.5.5.15 when subPath feature is used

Issue

When using a configmap with the subPath feature in 3.5.5.15, pod start fails with:

The error was: container_linux.go:247: starting container process caused "process_linux.go:359: container init caused \"rootfs_linux.go:54: mounting \\\"/var/lib/origin/openshift.local.volumes/pods/18bac66d-7386-11e7-9e39-005056af7709/volumes/kubernetes.io~configmap/filter-k8s-record-transform-conf\\\" to rootfs \\\"/var/lib/docker/devicemapper/mnt/3470f688d422b2c88874a6d2741f4c548ec5b980124b3ffa516089086a5f1983/rootfs\\\" at \\\"/var/lib/docker/devicemapper/mnt/3470f688d422b2c88874a6d2741f4c548ec5b980124b3ffa516089086a5f1983/rootfs/etc/fluent/configs.d/openshift/filter-k8s-record-transform.conf\\\" caused \\\"not a directory\\\"\""