Decouple state inspection and availability check

The state of a node should only be considered when calculating
resources, not when determining availability.  This makes the driver
consider any node that exists in the node inventory as available, and
take into account its state when determining available resources. All nodes
will be presented to Nova, but those that are in maintenence mode, have no
power state or have an error power state will present zero resources.

Closes-Bug: #1309048
Change-Id: Ia78294ac5d39955dac99d3d773751e8f7538a74d
Stop creating a swap partition when none was specified

Formerly, when the Nova flavor specified no swap partition, Ironic would
still create a 1mb swap partition to avoid certain issues. Those have
been fixed in previous patches. This patch corrects the behavior such
that Ironic will only create a swap partition when one is requested.

Closes-Bug: #1273785
Change-Id: I6f1c2de3fc1128fd92911fa5ffc737eb20a17409
Place root partition last so that it can always be expanded

Make the partitioning layout consistent by having the root partition
always be the last partition. This enables tools like cloud-init's
growroot utility to expand the root partition until the end of the disk,
regardless of the presence of a swap or ephemeral partition. In the
case where there is neither a swap nor ephemeral partition, the root
partition is the only partition created.

Closes-Bug: #1313606
Change-Id: I82492eb50530adc1f31e934f15f5c67462819a71
Merge "Decouple state inspection and availability check"
Merge "Stop creating a swap partition when none was specified"
Merge "Place root partition last so that it can always be expanded"
RPC_API_VERSION out of sync

This sets the RPC_API_VERSION for the conductor manager to be 1.15,
which is the same as the version on the API/client side.

A unit test was added to check that the RPC_API_VERSIONs are equal.

Comments in rpcapi.py and manager.py were added to remind readers
that the versions need to be in sync.

Change-Id: I047603d2d1117399978e98b9a93c9c32f512bbf1
Closes-Bug: #1317202