ironic should automatically fall back to using http instead of swift with redfish virtual media

[Julia Kreger]

Operators often don't consciously think of all of the dependencies to services, and may end up with a mostly default [redfish] configuration section when attempting to deploy a node.

By default, the use_swift configuration parameter is set to True, however operators might not have swift, and the deployments just fail at that point.

It would be really awesome if the service retries without swift automatically so the operator does not need to manually change configuration or know about the parameter upfront.