Check the PVC ref count on the node info cache to determine if a pod's
PVCs are in use. If they are and it is using ReadWriteOncePod, fail the
request.
kubernetes#60525 introduced
Balanced attached node volumes feature gate to include volume
count for prioritizing nodes. The reason for introducing this
flag was its usefulness in Red Hat OpenShift Online environment
which is not being used any more. So, removing the flag
as it helps in maintainability of the scheduler code base
as mentioned at kubernetes#101489 (comment)
