Simplify attachment of boot disk, get_as_boot_disk no longer needed
Add missing Disk.get_object method
Allow setting deviceName when attaching a disk
Add disks mocks
Check that server and disk destroy operation starts successfully
Implement get and delete requests
Handle 204 responses without body
Return excon response with same status as the api returned
Delete delete_operation api method that doesn't exist
Add mocks for operations and use them in disk and server
The caller need only specify either image_name OR snapshot + size
when creating a disk in a given zone.
This patch also removes the @default_zone variable being referenced
in several places (because it is not actually defined anywhere).