Comment 1 for bug 1647734

Currently curtin needs the following:

  - Don't raise an exception if we don't find a target root device
  - Detect that if the deployed image is snappy, that we don't need a root device
  - Only attempt to mount the rootdev if one is found
  - Allow curthooks to be skipped if our source is a dd-image source
  - Changes to curtin tools for integration testing of UC images

A prototype that needs refreshing is here: lp:~raharper/curtin/trunk.snappy-dd