Have CB2.0 record what disks are where and in use. [1/3]

This pull request records what physical disks are present, how they
can be accessed, and our best guess about which one the OS will wind
up installing on.

It also includes some OS install fixes, and a Sledgehammer update that
helps sanitize another annoyingly persistent disk signature.


 bin/crowbar                                           |  7 +++++++
 crowbar_framework/app/controllers/nodes_controller.rb |  4 ++++
 crowbar_framework/app/models/node.rb                  | 19 +++++++++++++++----
 crowbar_framework/app/models/node_role.rb             |  6 +++---
 crowbar_framework/config/routes.rb                    |  1 +
 5 files changed, 30 insertions(+), 7 deletions(-)

Crowbar-Pull-ID: 1861e20532f90489ad0409075a754cdb913aeb53

Crowbar-Release: development