[deltacloud-devel] Added Ability to Delete Provider

[Martyn Taylor]

This patch adds ability for deleting providers.

As discussed with sseago, this patch leaves any images removes all associated objects, but leaves any built images in limbo state.

Currently the provider can only be deleted, provided its associated cloud accounts contain no instances.  Since removing instances is not yet implemented, deleting provider is only managable when no associated instances have been started.

This patch will need to be readressed once multiple providers are supported, in order to address the issues with limbo images.