Remove ESXDriver from Juno.

1. Removes the VMwareESXDriver code in nova/virt/vmwareapi/driver.py
by either deleting the redundant methods or moving them to
VMwareVCDriver.
2. Changes the test cases to use VMwareVCDriver and also removes
duplicate test cases which were previously being testing both
VMwareESXDriver and VMwareVCDriver to just the latter.

DocImpact
Closes-Bug: #1346637
Change-Id: I718fc0ee67dbd625af00c20fa4e34b8a35015437
Merge "Remove ESXDriver from Juno."