Pod deployment fails due to "timeout expired waiting for volumes to attach" in OpenShift 3.x

Issue

Pod deployments are failing with these events:

# oc get events
LASTSEEN   FIRSTSEEN   COUNT     NAME      KIND      SUBOBJECT   TYPE      REASON        SOURCE                                                        MESSAGE
2m         2m          1         mypod     Pod                   Normal    Scheduled     default-scheduler                                             Successfully assigned mypod to node-0.example.com
1m         1m          1         mypod     Pod                   Warning   FailedMount   kubelet, node-0.example.com   Unable to mount volumes for pod "mypod_test(8d9831d3-21aa-11e8-b5ce-fa163e3ac0a2)": timeout expired waiting for volumes to attach/mount for pod "test"/"mypod". list of unattached/unmounted volumes=[pvol]
1m         1m          1         mypod     Pod                   Warning   FailedSync    kubelet, node-0.example.com   Error syncing pod