SSH virsh to use the new ManagementInterface

Add the new ManagementInterface to the SSH driver. Only the 'virsh'
virt_type is supported for now.

Implements: blueprint new-management-interface
Change-Id: I36b704e4d9daa902393b3f79405bf288d9ee0872
Adding swift temp url support

This patch will allow properly configured Glance servers to return a temporary
URL for an object hosted on Swift. It will require Glance to use Swift
as its backend. A temporary URL allow a deploy driver to download an image
from Glance without requiring an auth_token, which gives access more than
just Glance. This requires a set of config options: the Glance endpoint URL,
a shared secret temporary key, and the account configured in Glance to talk
to Swift with, which owns the container images are stored in.

A later patch will explore using the direct_url in Glance to simplify the
config options.

We/I need to add a note in the docs about Swift being a possible dependency
for Ironic deploys using IPA, along with how to set the Temp URL key.

Swift performance concerns will be addressed in this blueprint:
https://blueprints.launchpad.net/ironic/+spec/improve-swift-agent-downloads

SecurityImpact
DocImpact

Partial Implements: blueprint swift-temp-urls
Change-Id: I10e4784eee63e8edc9ba30a9c5004a08aa3a6d8e
Update_port should expect MACAlreadyExists

Conductor manager's update_port() method should include
exception.MACAlreadyExists in the list of expected exceptions.  This
will stop logging it as a traceback on the Conductor when a client
attempts to update a port and change its address to one that is already
registered.

Change-Id: Ic575e03da566c7b44bf6b72ac171633d80165ffc
Closes-Bug: #1348676
Merge "Update_port should expect MACAlreadyExists"
Merge "SSH virsh to use the new ManagementInterface"