Set the correct target versions for the RPC methods

This patch sets the correct target versions for the RPC methods in
the RPC API. This is a first step towards being able to enable rolling
upgrades for Ironic.

Partial-Bug: #1317300
Change-Id: I67ce731731c38e48b4f3180a423cbc18a3728903
Remove 'node' parameter from the Power interface

The node parameter is redundant since the node object is an attribute
of the task object.

Partial-Bug: #1312632
Change-Id: I4baa8526768a250e0cf047f56322039157772376
Merge "Remove 'node' parameter from the Power interface"