stacker version

v0.30.1-15-gdc0ada0

Describe the bug

If you attempt to build the stacker.yaml below it will fail.
The reason is that the /files directory is stripped away in the 'mybuild' layer. The files 'subuid' and 'subgid' are directly in /.

$ stacker build --layer-type=squashfs --layer-type=tar
...
error: lstat /files/subuid: no such file or directory
error: execute failed: exit status 1
error: exit status 1

$ cat stacker.yaml 
mybuild:
  from:
    type: scratch
  import:
    - path: /etc/subuid
      dest: /files/
    - path: /etc/subgid
      dest: /files

mytest:
  from: 
    type: docker
    url: docker://ubuntu:latest
  import:
    - stacker://mybuild/files/subuid
    - stacker://mybuild/files/subgid
  run: |
    ls -l /stacker

To reproduce

No response

Expected behavior

No response

Screenshots

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Additional context

No response