Draft of sheepdog support for nova disks

- Currently supports booting from a sheepdog virtual disk image (vdi)
  that already exists in glance. This requries the glance store to be
  sheepdog. Once the image is cloned for the VM, it is resized to fit
  the flavor.

- Cleanup works as expected.

TODO(scott-devoid):

- Test disk.local and disk.config support.
- Get snapshots to work.
- Get live migrations to work.

Remove debugging statements

Image deletion draft

Fix pep8 errors

fix

fix

Add dog file and clean up utils and imagebackend

Change sheepdog XML format

Work on snapshotting

Work on snapshotting

Hopefully get resize working

Fix sheepdog to use host-port config

Fix sheepdog to use host-port config

Fix sheepdog to use host-port config

Bug with source name.

resize working now?

i r dumb

Doing this this way is an anipattern.

Doing this this way is an anipattern.