Description of problem:
Adding subdirectory as Mount Path, although it shows (both on web & CLI) path is added, actually the path/files was not created successfully

Version-Release number of selected component (if applicable):
OpenShift Master: v3.6.171 (online version 3.5.1.79)
Kubernetes Master: v1.6.1+5115d708d7 

How reproducible:
Always

Steps to Reproduce:
1.Login and create a project
2.Create ConfigMap
$ oc create -f https://raw.githubusercontent.com/openshift-qe/v3-testfiles/master/configmap/configmap-example.yaml
3.Create DC
$ oc run myrun --image=aosqe/hello-openshift
4.Go to dc/myrun -> Configuration tab -> Add config files -> "Mount Path: /data" -> Click Add
5. Add another one, go to dc/myrun -> Configuration tab -> Add config files -> "Mount Path: /data/configmap" -> Click Add

6 Check volume in pod
$ oc exec myrun-x-xx ls /data
$ oc exec myrun-x-xx ls /data/configmap

Actual results:
6 Only show the files where key be exposed
6.1 $ oc exec <pod_name> ls /data
example.property.1
example.property.2
example.property.file
6.2 $ oc exec <pod_name> ls /data/configmap
ls: /data/configmap: No such file or directory
command terminated with exit code 1

Expected results:
6.2 files should be created under /data/configmap path and output should be:
$ oc exec <pod_name> ls /data/configmap
example.property.1
example.property.2
example.property.file

Additional info