Migrate away from rackspace_resource

Having Rackspace specific resources subclass a the rackspace_resource
does not replace the clients system wide. Use the cloud_backend to
acomplish this. That way any special configuration done with pyrax
will be used in any client call.
Change-Id: Ia6d548e606a42c608135cb66876419d1b339a06c
Make db API respect context show_deleted

Currently the soft-delete aware stuff in the DB api only respects
flags passed in directly, not the context.show_deleted, so align
the code with what is implied by existing comments and respect
the flag in the context too.

Change-Id: I88cd1a8862a2a53c314849e11d026182180bce9b
blueprint: request-scoping-policy
Openstack Trove (DBaaS) resource

Implementing Database as a Service (Trove) resource.

Implements: blueprint dbaas-trove-resource

Change-Id: I8a925ba586f4e29a5208797d97d0b5d9d05aa1e3
Merge "Migrate away from rackspace_resource"
Merge "Openstack Trove (DBaaS) resource"
Merge "Make db API respect context show_deleted"