Fix softlayer: delete custom code; rely on jclouds

- The SoftLayerFastVirtualGuestToNodeMetadata broke softlayer for me:
  when I provisioned a VM, the NodeMetadata returned had a null imageId
  and null OperatingSystem, which caused an NPE in
  JcloudsLocation.createUser.
- Deleting that class to rely on normal jclouds 1.8 fixed the problem
  for me.
This closes #193