The "Configure a Pod to Use a PersistentVolume for Storage"-task specifies that the content should be located on "/mnt/data" and not "/tmp/data", however this is not reflected in the yaml.
* update pod persistent volume example storage class
When binding to a manually created PersistentVolume, the claim must
disable dynamic provisioning by specifying an empty storage class.
Fixes#2803
* use specific storageclass
* revert gibibytes -> gigabytes change