Add mkfs to the baremetal-deploy-helper rootwrap

The nova-baremetal-deploy-helper uses the mkfs command to
format the ephemeral partition (if configured). The
command works today because it is also defined in the
compute.filters file but we should be explicit here.

Change-Id: I79c31ffd26ff92d35d3d9836f2a8954a9a07c2c0
Add boolean convertor to "create multiple servers" API

"create multiple servers" API contains "return_reservation_id" as an
attribute, and the attribute should be boolean. There are the other
boolean attributes such as "on_shared_storage" of evacuate API, they
can be passed with either boolean or string(e.g. "True"). For the
consistency of whole Nova APIs, this patch adds boolean convertors to
multiple_create API.

Change-Id: Id6f458a2ced869a31d5d25d661309973132e9360
Closes-Bug: #1281440
Fixes api samples for V2 os-assisted-volume-snapshots

Corrects the api samples for the V2 os-assisted-volume-snapshots.
The api samples for the create path were incorrect. This patch fixes
them so the documentation for the API will be correct. It doesn't fix
the input validation as it would be a backwards incompatible change.

Closes-Bug: 1286936

Change-Id: I66a9162e637e3d65bcbd7d033c6c173e67178fbe
Merge "Add boolean convertor to "create multiple servers" API"
Merge "Add mkfs to the baremetal-deploy-helper rootwrap"
Merge "Fixes api samples for V2 os-assisted-volume-snapshots"