Revert "mount and format ephemeral disk for vsphere"

This reverts the following commit
 * 385a9f9e402b9352835ae7c8385c2c8c04700f41
   "get correct persistent disk for vsphere"

 * 1e1d8749566c7dd879a7d16c93aa0ab4234a842f
   "Break up persistent and ephemeral disk code paths in platform and infrastructure"

 * 5a8b851efd4d5ade05516470c5173ee6584b40f8
   "rename devicePath to devicePathOrCid"

 * 6c78510ad6939e5762140e6ae10a51875dc24f5d
   "mount and format ephemeral disk for vsphere"

Signed-off-by: Nick Wade <nwade@pivotallabs.com>

Conflicts:
	go_agent/src/bosh/infrastructure/vsphere_infrastructure_test.go